thodg/libgit2

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d411751..fd84666 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -196,7 +196,7 @@ ELSE ()
 	ENABLE_WARNINGS(extra)
 
 	IF (CMAKE_SYSTEM_NAME MATCHES "(Solaris|SunOS)")
-		SET(CMAKE_C_FLAGS "-std=c99 -D_POSIX_C_SOURCE=200112L -D__EXTENSIONS__ -D_POSIX_PTHREAD_SEMANTICS ${CMAKE_C_FLAGS}")
+		SET(CMAKE_C_FLAGS "-D_POSIX_C_SOURCE=200112L -D__EXTENSIONS__ -D_POSIX_PTHREAD_SEMANTICS ${CMAKE_C_FLAGS}")
 	ENDIF()
 
 	SET(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -D_DEBUG -O0")
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index ca7515e..49edaec 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -1,7 +1,10 @@
 INCLUDE_DIRECTORIES(${LIBGIT2_INCLUDES})
+INCLUDE_DIRECTORIES(SYSTEM ${LIBGIT2_SYSTEM_INCLUDES})
 
 FILE(GLOB_RECURSE SRC_EXAMPLE_GIT2 network/*.c network/*.h common.?)
 ADD_EXECUTABLE(cgit2 ${SRC_EXAMPLE_GIT2})
+SET_TARGET_PROPERTIES(cgit2 PROPERTIES C_STANDARD 90)
+
 IF(WIN32 OR ANDROID)
 	TARGET_LINK_LIBRARIES(cgit2 git2)
 ELSE()
@@ -14,5 +17,6 @@ FOREACH(src_app ${SRC_EXAMPLE_APPS})
 	IF(NOT ${app_name} STREQUAL "common")
 		ADD_EXECUTABLE(${app_name} ${src_app} "common.c")
 		TARGET_LINK_LIBRARIES(${app_name} git2)
+		SET_TARGET_PROPERTIES(${app_name} PROPERTIES C_STANDARD 90)
 	ENDIF()
 ENDFOREACH()
diff --git a/examples/general.c b/examples/general.c
index 0780d3d..15b415a 100644
--- a/examples/general.c
+++ b/examples/general.c
@@ -145,11 +145,13 @@ static void oid_parsing(git_oid *oid)
 	 */
 	git_oid_fromstr(oid, hex);
 
-	// Once we've converted the string into the oid value, we can get the raw
-	// value of the SHA by accessing `oid.id`
-
-	// Next we will convert the 20 byte raw SHA1 value to a human readable 40
-	// char hex value.
+	/*
+	 * Once we've converted the string into the oid value, we can get the raw
+	 * value of the SHA by accessing `oid.id`
+	 *
+	 * Next we will convert the 20 byte raw SHA1 value to a human readable 40
+	 * char hex value.
+	 */
 	printf("\n*Raw to Hex*\n");
 	out[GIT_OID_HEXSZ] = '\0';
 
diff --git a/examples/network/clone.c b/examples/network/clone.c
index 540000b..ce4b6ae 100644
--- a/examples/network/clone.c
+++ b/examples/network/clone.c
@@ -48,7 +48,7 @@ static void print_progress(const progress_data *pd)
 
 static int sideband_progress(const char *str, int len, void *payload)
 {
-	(void)payload; // unused
+	(void)payload; /* unused */
 
 	printf("remote: %.*s", len, str);
 	fflush(stdout);
@@ -82,15 +82,15 @@ int do_clone(git_repository *repo, int argc, char **argv)
 	const char *path = argv[2];
 	int error;
 
-	(void)repo; // unused
+	(void)repo; /* unused */
 
-	// Validate args
+	/* Validate args */
 	if (argc < 3) {
 		printf ("USAGE: %s <url> <path>\n", argv[0]);
 		return -1;
 	}
 
-	// Set up options
+	/* Set up options */
 	checkout_opts.checkout_strategy = GIT_CHECKOUT_SAFE;
 	checkout_opts.progress_cb = checkout_progress;
 	checkout_opts.progress_payload = &pd;
@@ -100,7 +100,7 @@ int do_clone(git_repository *repo, int argc, char **argv)
 	clone_opts.fetch_opts.callbacks.credentials = cred_acquire_cb;
 	clone_opts.fetch_opts.callbacks.payload = &pd;
 
-	// Do the clone
+	/* Do the clone */
 	error = git_clone(&cloned_repo, url, path, &clone_opts);
 	printf("\n");
 	if (error != 0) {
diff --git a/examples/network/index-pack.c b/examples/network/index-pack.c
index 314f211..e926102 100644
--- a/examples/network/index-pack.c
+++ b/examples/network/index-pack.c
@@ -19,8 +19,10 @@
 #endif
 #include "common.h"
 
-// This could be run in the main loop whilst the application waits for
-// the indexing to finish in a worker thread
+/*
+ * This could be run in the main loop whilst the application waits for
+ * the indexing to finish in a worker thread
+ */
 static int index_cb(const git_transfer_progress *stats, void *data)
 {
 	(void)data;
diff --git a/examples/network/ls-remote.c b/examples/network/ls-remote.c
index 9329da5..fb258ac 100644
--- a/examples/network/ls-remote.c
+++ b/examples/network/ls-remote.c
@@ -12,7 +12,7 @@ static int use_remote(git_repository *repo, char *name)
 	size_t refs_len, i;
 	git_remote_callbacks callbacks = GIT_REMOTE_CALLBACKS_INIT;
 
-	// Find the remote by name
+	/* Find the remote by name */
 	error = git_remote_lookup(&remote, repo, name);
 	if (error < 0) {
 		error = git_remote_create_anonymous(&remote, repo, name);
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 2deed5f..be733cc 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -16,6 +16,7 @@ SET(LIBGIT2_INCLUDES
 	"${CMAKE_CURRENT_BINARY_DIR}"
 	"${libgit2_SOURCE_DIR}/src"
 	"${libgit2_SOURCE_DIR}/include")
+SET(LIBGIT2_SYSTEM_INCLUDES "")
 SET(LIBGIT2_LIBS "")
 
 # Installation paths
@@ -94,7 +95,7 @@ ADD_FEATURE_INFO(threadsafe THREADSAFE "threadsafe support")
 
 IF (WIN32 AND EMBED_SSH_PATH)
 	FILE(GLOB SRC_SSH "${EMBED_SSH_PATH}/src/*.c")
-	LIST(APPEND LIBGIT2_INCLUDES "${EMBED_SSH_PATH}/include")
+	LIST(APPEND LIBGIT2_SYSTEM_INCLUDES "${EMBED_SSH_PATH}/include")
 	FILE(WRITE "${EMBED_SSH_PATH}/src/libssh2_config.h" "#define HAVE_WINCNG\n#define LIBSSH2_WINCNG\n#include \"../win32/libssh2_config.h\"")
 	SET(GIT_SSH 1)
 ENDIF()
@@ -107,7 +108,7 @@ IF (WIN32 AND WINHTTP)
 	IF (MINGW)
 		ADD_SUBDIRECTORY("${libgit2_SOURCE_DIR}/deps/winhttp" "${libgit2_BINARY_DIR}/deps/winhttp")
 		LIST(APPEND LIBGIT2_LIBS winhttp)
-		LIST(APPEND LIBGIT2_INCLUDES "${libgit2_SOURCE_DIR}/deps/winhttp")
+		LIST(APPEND LIBGIT2_SYSTEM_INCLUDES "${libgit2_SOURCE_DIR}/deps/winhttp")
 	ELSE()
 		LIST(APPEND LIBGIT2_LIBS "winhttp")
 		LIST(APPEND LIBGIT2_PC_LIBS "-lwinhttp")
@@ -121,7 +122,7 @@ ELSE ()
 	ENDIF ()
 	IF (CURL_FOUND)
 		SET(GIT_CURL 1)
-		LIST(APPEND LIBGIT2_INCLUDES ${CURL_INCLUDE_DIRS})
+		LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${CURL_INCLUDE_DIRS})
 		LIST(APPEND LIBGIT2_LIBS ${CURL_LIBRARIES})
 		LIST(APPEND LIBGIT2_PC_LIBS ${CURL_LDFLAGS})
 	ENDIF()
@@ -174,7 +175,7 @@ IF (USE_HTTPS)
 		ENDIF()
 
 		SET(GIT_SECURE_TRANSPORT 1)
-		LIST(APPEND LIBGIT2_INCLUDES ${SECURITY_INCLUDE_DIR})
+		LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${SECURITY_INCLUDE_DIR})
 		LIST(APPEND LIBGIT2_LIBS ${COREFOUNDATION_LIBRARIES} ${SECURITY_LIBRARIES})
 		LIST(APPEND LIBGIT2_PC_LIBS ${COREFOUNDATION_LDFLAGS} ${SECURITY_LDFLAGS})
 	ELSEIF (HTTPS_BACKEND STREQUAL "OpenSSL")
@@ -183,7 +184,7 @@ IF (USE_HTTPS)
 		ENDIF()
 
 		SET(GIT_OPENSSL 1)
-		LIST(APPEND LIBGIT2_INCLUDES ${OPENSSL_INCLUDE_DIR})
+		LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${OPENSSL_INCLUDE_DIR})
 		LIST(APPEND LIBGIT2_LIBS ${OPENSSL_LIBRARIES})
 		LIST(APPEND LIBGIT2_PC_LIBS ${OPENSSL_LDFLAGS})
 		LIST(APPEND LIBGIT2_PC_REQUIRES "openssl")
@@ -230,7 +231,7 @@ IF (USE_HTTPS)
 		ENDIF()
 
 		SET(GIT_MBEDTLS 1)
-		LIST(APPEND LIBGIT2_INCLUDES ${MBEDTLS_INCLUDE_DIR})
+		LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${MBEDTLS_INCLUDE_DIR})
 		LIST(APPEND LIBGIT2_LIBS ${MBEDTLS_LIBRARIES})
 		# mbedTLS has no pkgconfig file, hence we can't require it
 		# https://github.com/ARMmbed/mbedtls/issues/228
@@ -285,7 +286,7 @@ ELSEIF (SHA1_BACKEND STREQUAL "mbedTLS")
 	ADD_FEATURE_INFO(SHA ON "using mbedTLS")
 	SET(GIT_SHA1_MBEDTLS 1)
 	FILE(GLOB SRC_SHA1 hash/hash_mbedtls.c)
-	LIST(APPEND LIBGIT2_INCLUDES ${MBEDTLS_INCLUDE_DIR})
+	LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${MBEDTLS_INCLUDE_DIR})
 	LIST(APPEND LIBGIT2_LIBS ${MBEDTLS_LIBRARIES})
 	# mbedTLS has no pkgconfig file, hence we can't require it
 	# https://github.com/ARMmbed/mbedtls/issues/228
@@ -298,21 +299,21 @@ ENDIF()
 # Include POSIX regex when it is required
 IF(WIN32 OR AMIGA OR CMAKE_SYSTEM_NAME MATCHES "(Solaris|SunOS)")
 	ADD_SUBDIRECTORY("${libgit2_SOURCE_DIR}/deps/regex" "${libgit2_BINARY_DIR}/deps/regex")
-	LIST(APPEND LIBGIT2_INCLUDES "${libgit2_SOURCE_DIR}/deps/regex")
+	LIST(APPEND LIBGIT2_SYSTEM_INCLUDES "${libgit2_SOURCE_DIR}/deps/regex")
 	LIST(APPEND LIBGIT2_OBJECTS $<TARGET_OBJECTS:regex>)
 ENDIF()
 
 # Optional external dependency: http-parser
 FIND_PACKAGE(HTTP_Parser)
 IF (USE_EXT_HTTP_PARSER AND HTTP_PARSER_FOUND AND HTTP_PARSER_VERSION_MAJOR EQUAL 2)
-	LIST(APPEND LIBGIT2_INCLUDES ${HTTP_PARSER_INCLUDE_DIRS})
+	LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${HTTP_PARSER_INCLUDE_DIRS})
 	LIST(APPEND LIBGIT2_LIBS ${HTTP_PARSER_LIBRARIES})
 	LIST(APPEND LIBGIT2_PC_LIBS "-lhttp_parser")
 	ADD_FEATURE_INFO(http-parser ON "http-parser support")
 ELSE()
 	MESSAGE(STATUS "http-parser version 2 was not found or disabled; using bundled 3rd-party sources.")
 	ADD_SUBDIRECTORY("${libgit2_SOURCE_DIR}/deps/http-parser" "${libgit2_BINARY_DIR}/deps/http-parser")
-	LIST(APPEND LIBGIT2_INCLUDES "${libgit2_SOURCE_DIR}/deps/http-parser")
+	LIST(APPEND LIBGIT2_SYSTEM_INCLUDES "${libgit2_SOURCE_DIR}/deps/http-parser")
 	LIST(APPEND LIBGIT2_OBJECTS "$<TARGET_OBJECTS:http-parser>")
 	ADD_FEATURE_INFO(http-parser ON "http-parser support (bundled)")
 ENDIF()
@@ -321,7 +322,7 @@ ENDIF()
 IF(NOT USE_BUNDLED_ZLIB)
 	FIND_PACKAGE(ZLIB)
 	IF(ZLIB_FOUND)
-		LIST(APPEND LIBGIT2_INCLUDES ${ZLIB_INCLUDE_DIRS})
+		LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${ZLIB_INCLUDE_DIRS})
 		LIST(APPEND LIBGIT2_LIBS ${ZLIB_LIBRARIES})
 		IF(APPLE OR CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
 			LIST(APPEND LIBGIT2_LIBS "z")
@@ -336,7 +337,7 @@ IF(NOT USE_BUNDLED_ZLIB)
 ENDIF()
 IF(USE_BUNDLED_ZLIB OR NOT ZLIB_FOUND)
 	ADD_SUBDIRECTORY("${libgit2_SOURCE_DIR}/deps/zlib" "${libgit2_BINARY_DIR}/deps/zlib")
-	LIST(APPEND LIBGIT2_INCLUDES "${libgit2_SOURCE_DIR}/deps/zlib")
+	LIST(APPEND LIBGIT2_SYSTEM_INCLUDES "${libgit2_SOURCE_DIR}/deps/zlib")
 	LIST(APPEND LIBGIT2_OBJECTS $<TARGET_OBJECTS:zlib>)
 	ADD_FEATURE_INFO(zlib ON "using bundled zlib")
 ENDIF()
@@ -347,7 +348,7 @@ IF (USE_SSH)
 ENDIF()
 IF (LIBSSH2_FOUND)
 	SET(GIT_SSH 1)
-	LIST(APPEND LIBGIT2_INCLUDES ${LIBSSH2_INCLUDE_DIRS})
+	LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${LIBSSH2_INCLUDE_DIRS})
 	LIST(APPEND LIBGIT2_LIBS ${LIBSSH2_LIBRARIES})
 	LIST(APPEND LIBGIT2_PC_LIBS ${LIBSSH2_LDFLAGS})
 
@@ -376,7 +377,7 @@ IF (USE_ICONV)
 ENDIF()
 IF (ICONV_FOUND)
 	SET(GIT_USE_ICONV 1)
-	LIST(APPEND LIBGIT2_INCLUDES ${ICONV_INCLUDE_DIR})
+	LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${ICONV_INCLUDE_DIR})
 	LIST(APPEND LIBGIT2_LIBS ${ICONV_LIBRARIES})
 	LIST(APPEND LIBGIT2_PC_LIBS ${ICONV_LIBRARIES})
 ENDIF()
@@ -449,19 +450,24 @@ CONFIGURE_FILE(features.h.in git2/sys/features.h)
 SET(LIBGIT2_SOURCES ${SRC_H} ${SRC_GIT2} ${SRC_OS} ${SRC_SSH} ${SRC_SHA1})
 
 ADD_LIBRARY(git2internal OBJECT ${LIBGIT2_SOURCES})
+SET_TARGET_PROPERTIES(git2internal PROPERTIES C_STANDARD 90)
 IDE_SPLIT_SOURCES(git2internal)
 LIST(APPEND LIBGIT2_OBJECTS $<TARGET_OBJECTS:git2internal>)
 
 IF (${CMAKE_VERSION} VERSION_LESS 2.8.12)
 	INCLUDE_DIRECTORIES(${LIBGIT2_INCLUDES})
+	INCLUDE_DIRECTORIES(SYSTEM ${LIBGIT2_SYSTEM_INCLUDES})
 ELSE()
 	TARGET_INCLUDE_DIRECTORIES(git2internal
 	    PRIVATE ${LIBGIT2_INCLUDES}
 	    PUBLIC ${libgit2_SOURCE_DIR}/include)
+	TARGET_INCLUDE_DIRECTORIES(git2internal
+	    SYSTEM PRIVATE ${LIBGIT2_SYSTEM_INCLUDES})
 ENDIF()
 
 SET(LIBGIT2_OBJECTS ${LIBGIT2_OBJECTS} PARENT_SCOPE)
 SET(LIBGIT2_INCLUDES ${LIBGIT2_INCLUDES} PARENT_SCOPE)
+SET(LIBGIT2_SYSTEM_INCLUDES ${LIBGIT2_SYSTEM_INCLUDES} PARENT_SCOPE)
 SET(LIBGIT2_LIBS ${LIBGIT2_LIBS} PARENT_SCOPE)
 
 IF(XCODE_VERSION)
@@ -475,6 +481,7 @@ ENDIF()
 ADD_LIBRARY(git2 ${WIN_RC} ${LIBGIT2_OBJECTS})
 TARGET_LINK_LIBRARIES(git2 ${LIBGIT2_LIBS})
 
+SET_TARGET_PROPERTIES(git2 PROPERTIES C_STANDARD 90)
 SET_TARGET_PROPERTIES(git2 PROPERTIES LIBRARY_OUTPUT_DIRECTORY ${libgit2_BINARY_DIR})
 SET_TARGET_PROPERTIES(git2 PROPERTIES RUNTIME_OUTPUT_DIRECTORY ${libgit2_BINARY_DIR})
 SET_TARGET_PROPERTIES(git2 PROPERTIES ARCHIVE_OUTPUT_DIRECTORY ${libgit2_BINARY_DIR})
diff --git a/src/common.h b/src/common.h
index 44063be..cb980c1 100644
--- a/src/common.h
+++ b/src/common.h
@@ -17,8 +17,10 @@
 /** Declare a function as always inlined. */
 #if defined(_MSC_VER)
 # define GIT_INLINE(type) static __inline type
+#elif defined(__GNUC__)
+# define GIT_INLINE(type) static __inline__ type
 #else
-# define GIT_INLINE(type) static inline type
+# define GIT_INLINE(type) static type
 #endif
 
 /** Support for gcc/clang __has_builtin intrinsic */
diff --git a/src/khash.h b/src/khash.h
index 71eb583..40e2d18 100644
--- a/src/khash.h
+++ b/src/khash.h
@@ -146,8 +146,10 @@ typedef unsigned long long khint64_t;
 #ifndef kh_inline
 #ifdef _MSC_VER
 #define kh_inline __inline
+#elif defined(__GNUC__)
+#define kh_inline __inline__
 #else
-#define kh_inline inline
+#define kh_inline
 #endif
 #endif /* kh_inline */
 
diff --git a/src/notes.c b/src/notes.c
index b4c0122..ebab0cd 100644
--- a/src/notes.c
+++ b/src/notes.c
@@ -285,7 +285,7 @@ static int note_write(
 	git_oid oid;
 	git_tree *tree = NULL;
 
-	// TODO: should we apply filters?
+	/* TODO: should we apply filters? */
 	/* create note object */
 	if ((error = git_blob_create_frombuffer(&oid, repo, note, strlen(note))) < 0)
 		goto cleanup;
diff --git a/src/refspec.c b/src/refspec.c
index aa6682b..f429776 100644
--- a/src/refspec.c
+++ b/src/refspec.c
@@ -16,7 +16,7 @@
 
 int git_refspec__parse(git_refspec *refspec, const char *input, bool is_fetch)
 {
-	// Ported from https://github.com/git/git/blob/f06d47e7e0d9db709ee204ed13a8a7486149f494/remote.c#L518-636
+	/* Ported from https://github.com/git/git/blob/f06d47e7e0d9db709ee204ed13a8a7486149f494/remote.c#L518-636 */
 
 	size_t llen;
 	int is_glob = 0;
diff --git a/src/signature.c b/src/signature.c
index cd68523..286d0a6 100644
--- a/src/signature.c
+++ b/src/signature.c
@@ -247,7 +247,7 @@ int git_signature__parse(git_signature *sig, const char **buffer_out,
 
 			if ((tz_start[0] != '-' && tz_start[0] != '+') ||
 				git__strtol32(&offset, tz_start + 1, &tz_end, 10) < 0) {
-				//malformed timezone, just assume it's zero
+				/* malformed timezone, just assume it's zero */
 				offset = 0;
 			}
 
diff --git a/src/streams/mbedtls.c b/src/streams/mbedtls.c
index 0a49a36..7cecb2a 100644
--- a/src/streams/mbedtls.c
+++ b/src/streams/mbedtls.c
@@ -26,12 +26,23 @@
 #define GIT_DEFAULT_CERT_LOCATION NULL
 #endif
 
+/* Work around C90-conformance issues */
+#if defined(_MSC_VER)
+# define inline __inline
+#elif defined(__GNUC__)
+# define inline __inline__
+#else
+# define inline
+#endif
+
 #include <mbedtls/config.h>
 #include <mbedtls/ssl.h>
 #include <mbedtls/error.h>
 #include <mbedtls/entropy.h>
 #include <mbedtls/ctr_drbg.h>
 
+#undef inline
+
 mbedtls_ssl_config *git__ssl_conf;
 mbedtls_entropy_context *mbedtls_entropy;
 
diff --git a/src/trailer.c b/src/trailer.c
index 24c8847..dc8d1ab 100644
--- a/src/trailer.c
+++ b/src/trailer.c
@@ -36,7 +36,7 @@ static const char *next_line(const char *str)
 	if (nl) {
 		return nl + 1;
 	} else {
-		// return pointer to the NUL terminator:
+		/* return pointer to the NUL terminator: */
 		return str + strlen(str);
 	}
 }
@@ -310,12 +310,12 @@ int git_message_trailers(git_message_trailer_array *trailer_arr, const char *mes
 				}
 
 				if (isalnum(*ptr) || *ptr == '-') {
-					// legal key character
+					/* legal key character */
 					NEXT(S_KEY);
 				}
 
 				if (*ptr == ' ' || *ptr == '\t') {
-					// optional whitespace before separator
+					/* optional whitespace before separator */
 					*ptr = 0;
 					NEXT(S_KEY_WS);
 				}
@@ -325,7 +325,7 @@ int git_message_trailers(git_message_trailer_array *trailer_arr, const char *mes
 					NEXT(S_SEP_WS);
 				}
 
-				// illegal character
+				/* illegal character */
 				GOTO(S_IGNORE);
 			}
 			case S_KEY_WS: {
@@ -341,7 +341,7 @@ int git_message_trailers(git_message_trailer_array *trailer_arr, const char *mes
 					NEXT(S_SEP_WS);
 				}
 
-				// illegal character
+				/* illegal character */
 				GOTO(S_IGNORE);
 			}
 			case S_SEP_WS: {
@@ -369,7 +369,7 @@ int git_message_trailers(git_message_trailer_array *trailer_arr, const char *mes
 			}
 			case S_VALUE_NL: {
 				if (*ptr == ' ') {
-					// continuation;
+					/* continuation; */
 					NEXT(S_VALUE);
 				}
 
diff --git a/src/transports/smart.c b/src/transports/smart.c
index 619a81f..69c129b 100644
--- a/src/transports/smart.c
+++ b/src/transports/smart.c
@@ -82,7 +82,7 @@ static bool is_malformed_http_header(const char *http_header)
 	const char *c;
 	int name_len;
 
-	// Disallow \r and \n
+	/* Disallow \r and \n */
 	c = strchr(http_header, '\r');
 	if (c)
 		return true;
@@ -90,7 +90,7 @@ static bool is_malformed_http_header(const char *http_header)
 	if (c)
 		return true;
 
-	// Require a header name followed by :
+	/* Require a header name followed by : */
 	name_len = http_header_name_length(http_header);
 	if (name_len < 1)
 		return true;
@@ -112,7 +112,7 @@ static bool is_forbidden_custom_header(const char *custom_header)
 	unsigned long i;
 	int name_len = http_header_name_length(custom_header);
 
-	// Disallow headers that we set
+	/* Disallow headers that we set */
 	for (i = 0; i < ARRAY_SIZE(forbidden_custom_headers); i++)
 		if (strncmp(forbidden_custom_headers[i], custom_header, name_len) == 0)
 			return true;
diff --git a/src/win32/posix_w32.c b/src/win32/posix_w32.c
index f51e1e5..8617e45 100644
--- a/src/win32/posix_w32.c
+++ b/src/win32/posix_w32.c
@@ -832,7 +832,7 @@ int p_mkstemp(char *tmp_path)
 		return -1;
 #endif
 
-	return p_open(tmp_path, O_RDWR | O_CREAT | O_EXCL, 0744); //-V536
+	return p_open(tmp_path, O_RDWR | O_CREAT | O_EXCL, 0744); /* -V536 */
 }
 
 int p_access(const char* path, mode_t mode)
diff --git a/src/xdiff/xdiffi.c b/src/xdiff/xdiffi.c
index 3a71ef6..97db054 100644
--- a/src/xdiff/xdiffi.c
+++ b/src/xdiff/xdiffi.c
@@ -33,8 +33,10 @@
 /** Declare a function as always inlined. */
 #if defined(_MSC_VER)
 # define XDL_INLINE(type) static __inline type
+#elif defined(__GNUC__)
+# define XDL_INLINE(type) static __inline__ type
 #else
-# define XDL_INLINE(type) static inline type
+#define XDG_INLINE(type) static type
 #endif
 
 typedef struct s_xdpsplit {
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 82bf6d0..d75114b 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -32,9 +32,11 @@ SET_SOURCE_FILES_PROPERTIES(
 	PROPERTIES OBJECT_DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/clar.suite)
 
 INCLUDE_DIRECTORIES(${LIBGIT2_INCLUDES})
+INCLUDE_DIRECTORIES(SYSTEM ${LIBGIT2_SYSTEM_INCLUDES})
 
 ADD_EXECUTABLE(libgit2_clar ${SRC_CLAR} ${SRC_TEST} ${LIBGIT2_OBJECTS})
 
+SET_TARGET_PROPERTIES(libgit2_clar PROPERTIES C_STANDARD 90)
 SET_TARGET_PROPERTIES(libgit2_clar PROPERTIES RUNTIME_OUTPUT_DIRECTORY ${libgit2_BINARY_DIR})
 
 IF (${CMAKE_VERSION} VERSION_LESS 2.8.12)
diff --git a/tests/checkout/index.c b/tests/checkout/index.c
index a649d85..69252e3 100644
--- a/tests/checkout/index.c
+++ b/tests/checkout/index.c
@@ -146,7 +146,7 @@ void test_checkout_index__honor_coresymlinks_default(void)
 	const char *url = git_repository_path(g_repo);
 
 	cl_assert(getcwd(cwd, sizeof(cwd)) != NULL);
-	cl_assert_equal_i(0, p_mkdir("readonly", 0555)); // Read-only directory
+	cl_assert_equal_i(0, p_mkdir("readonly", 0555)); /* Read-only directory */
 	cl_assert_equal_i(0, chdir("readonly"));
 	cl_git_pass(git_repository_init(&repo, "../symlink.git", true));
 	cl_assert_equal_i(0, chdir(cwd));
diff --git a/tests/checkout/tree.c b/tests/checkout/tree.c
index a78bf82..a69574b 100644
--- a/tests/checkout/tree.c
+++ b/tests/checkout/tree.c
@@ -915,7 +915,7 @@ void test_checkout_tree__target_directory_from_bare(void)
 
 void test_checkout_tree__extremely_long_file_name(void)
 {
-	// A utf-8 string with 83 characters, but 249 bytes.
+	/* A utf-8 string with 83 characters, but 249 bytes. */
 	const char *longname = "\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97";
 	char path[1024];
 
diff --git a/tests/cherrypick/workdir.c b/tests/cherrypick/workdir.c
index d83f54b..e43bb08 100644
--- a/tests/cherrypick/workdir.c
+++ b/tests/cherrypick/workdir.c
@@ -12,7 +12,7 @@
 static git_repository *repo;
 static git_index *repo_index;
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_cherrypick_workdir__initialize(void)
 {
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
diff --git a/tests/commit/parse.c b/tests/commit/parse.c
index e61589d..47ec6dd 100644
--- a/tests/commit/parse.c
+++ b/tests/commit/parse.c
@@ -3,7 +3,7 @@
 #include "commit.h"
 #include "signature.h"
 
-// Fixture setup
+/* Fixture setup */
 static git_repository *g_repo;
 void test_commit_parse__initialize(void)
 {
@@ -15,7 +15,7 @@ void test_commit_parse__cleanup(void)
 }
 
 
-// Header parsing
+/* Header parsing */
 typedef struct {
 	const char *line;
 	const char *header;
@@ -70,7 +70,7 @@ void test_commit_parse__header(void)
 }
 
 
-// Signature parsing
+/* Signature parsing */
 typedef struct {
 	const char *string;
 	const char *header;
@@ -89,27 +89,27 @@ passing_signature_test_case passing_signature_cases[] = {
 	{"committer Vicent Marti <tanoku@gmail.com> 123456 +0000 \n", "committer ", "Vicent Marti", "tanoku@gmail.com", 123456, 0},
 	{"committer Vicent Marti <tanoku@gmail.com> 123456 +0100 \n", "committer ", "Vicent Marti", "tanoku@gmail.com", 123456, 60},
 	{"committer Vicent Marti <tanoku@gmail.com> 123456 -0100 \n", "committer ", "Vicent Marti", "tanoku@gmail.com", 123456, -60},
-	// Parse a signature without an author field
+	/* Parse a signature without an author field */
 	{"committer <tanoku@gmail.com> 123456 -0100 \n", "committer ", "", "tanoku@gmail.com", 123456, -60},
-	// Parse a signature without an author field
+	/* Parse a signature without an author field */
 	{"committer  <tanoku@gmail.com> 123456 -0100 \n", "committer ", "", "tanoku@gmail.com", 123456, -60},
-	// Parse a signature with an empty author field
+	/* Parse a signature with an empty author field */
 	{"committer   <tanoku@gmail.com> 123456 -0100 \n", "committer ", "", "tanoku@gmail.com", 123456, -60},
-	// Parse a signature with an empty email field
+	/* Parse a signature with an empty email field */
 	{"committer Vicent Marti <> 123456 -0100 \n", "committer ", "Vicent Marti", "", 123456, -60},
-	// Parse a signature with an empty email field
+	/* Parse a signature with an empty email field */
 	{"committer Vicent Marti < > 123456 -0100 \n", "committer ", "Vicent Marti", "", 123456, -60},
-	// Parse a signature with empty name and email
+	/* Parse a signature with empty name and email */
 	{"committer <> 123456 -0100 \n", "committer ", "", "", 123456, -60},
-	// Parse a signature with empty name and email
+	/* Parse a signature with empty name and email */
 	{"committer  <> 123456 -0100 \n", "committer ", "", "", 123456, -60},
-	// Parse a signature with empty name and email
+	/* Parse a signature with empty name and email */
 	{"committer  < > 123456 -0100 \n", "committer ", "", "", 123456, -60},
-	// Parse an obviously invalid signature
+	/* Parse an obviously invalid signature */
 	{"committer foo<@bar> 123456 -0100 \n", "committer ", "foo", "@bar", 123456, -60},
-	// Parse an obviously invalid signature
+	/* Parse an obviously invalid signature */
 	{"committer    foo<@bar> 123456 -0100 \n", "committer ", "foo", "@bar", 123456, -60},
-	// Parse an obviously invalid signature
+	/* Parse an obviously invalid signature */
 	{"committer <>\n", "committer ", "", "", 0, 0},
 	{"committer Vicent Marti <tanoku@gmail.com> 123456 -1500 \n", "committer ", "Vicent Marti", "tanoku@gmail.com", 123456, 0},
 	{"committer Vicent Marti <tanoku@gmail.com> 123456 +0163 \n", "committer ", "Vicent Marti", "tanoku@gmail.com", 123456, 0},
@@ -173,65 +173,65 @@ void test_commit_parse__signature(void)
 
 
 static char *failing_commit_cases[] = {
-// empty commit
+/* empty commit */
 "",
-// random garbage
+/* random garbage */
 "asd97sa9du902e9a0jdsuusad09as9du098709aweu8987sd\n",
-// broken endlines 1
+/* broken endlines 1 */
 "tree f6c0dad3c7b3481caa9d73db21f91964894a945b\r\n\
 parent 05452d6349abcd67aa396dfb28660d765d8b2a36\r\n\
 author Vicent Marti <tanoku@gmail.com> 1273848544 +0200\r\n\
 committer Vicent Marti <tanoku@gmail.com> 1273848544 +0200\r\n\
 \r\n\
 a test commit with broken endlines\r\n",
-// broken endlines 2
+/* broken endlines 2 */
 "tree f6c0dad3c7b3481caa9d73db21f91964894a945b\
 parent 05452d6349abcd67aa396dfb28660d765d8b2a36\
 author Vicent Marti <tanoku@gmail.com> 1273848544 +0200\
 committer Vicent Marti <tanoku@gmail.com> 1273848544 +0200\
 \
 another test commit with broken endlines",
-// starting endlines
+/* starting endlines */
 "\ntree f6c0dad3c7b3481caa9d73db21f91964894a945b\n\
 parent 05452d6349abcd67aa396dfb28660d765d8b2a36\n\
 author Vicent Marti <tanoku@gmail.com> 1273848544 +0200\n\
 committer Vicent Marti <tanoku@gmail.com> 1273848544 +0200\n\
 \n\
 a test commit with a starting endline\n",
-// corrupted commit 1
+/* corrupted commit 1 */
 "tree f6c0dad3c7b3481caa9d73db21f91964894a945b\n\
 parent 05452d6349abcd67aa396df",
-// corrupted commit 2
+/* corrupted commit 2 */
 "tree f6c0dad3c7b3481caa9d73db21f91964894a945b\n\
 parent ",
-// corrupted commit 3
+/* corrupted commit 3 */
 "tree f6c0dad3c7b3481caa9d73db21f91964894a945b\n\
 parent ",
-// corrupted commit 4
+/* corrupted commit 4 */
 "tree f6c0dad3c7b3481caa9d73db21f91964894a945b\n\
 par",
 };
 
 
 static char *passing_commit_cases[] = {
-// simple commit with no message
+/* simple commit with no message */
 "tree 1810dff58d8a660512d4832e740f692884338ccd\n\
 author Vicent Marti <tanoku@gmail.com> 1273848544 +0200\n\
 committer Vicent Marti <tanoku@gmail.com> 1273848544 +0200\n\
 \n",
-// simple commit, no parent
+/* simple commit, no parent */
 "tree 1810dff58d8a660512d4832e740f692884338ccd\n\
 author Vicent Marti <tanoku@gmail.com> 1273848544 +0200\n\
 committer Vicent Marti <tanoku@gmail.com> 1273848544 +0200\n\
 \n\
 a simple commit which works\n",
-// simple commit, no parent, no newline in message
+/* simple commit, no parent, no newline in message */
 "tree 1810dff58d8a660512d4832e740f692884338ccd\n\
 author Vicent Marti <tanoku@gmail.com> 1273848544 +0200\n\
 committer Vicent Marti <tanoku@gmail.com> 1273848544 +0200\n\
 \n\
 a simple commit which works",
-// simple commit, 1 parent
+/* simple commit, 1 parent */
 "tree 1810dff58d8a660512d4832e740f692884338ccd\n\
 parent e90810b8df3e80c413d903f631643c716887138d\n\
 author Vicent Marti <tanoku@gmail.com> 1273848544 +0200\n\
@@ -317,7 +317,7 @@ void test_commit_parse__entire_commit(void)
 }
 
 
-// query the details on a parsed commit
+/* query the details on a parsed commit */
 void test_commit_parse__details0(void) {
 	static const char *commit_ids[] = {
 		"a4a7dce85cf63874e984719f4fdd239f5145052f", /* 0 */
@@ -365,7 +365,7 @@ void test_commit_parse__details0(void) {
 			old_parent = parent;
 			cl_git_pass(git_commit_parent(&parent, commit, p));
 			cl_assert(parent != NULL);
-			cl_assert(git_commit_author(parent) != NULL); // is it really a commit?
+			cl_assert(git_commit_author(parent) != NULL); /* is it really a commit? */
 		}
 		git_commit_free(old_parent);
 		git_commit_free(parent);
diff --git a/tests/commit/signature.c b/tests/commit/signature.c
index 286079f..78ddbbe 100644
--- a/tests/commit/signature.c
+++ b/tests/commit/signature.c
@@ -59,7 +59,7 @@ void test_commit_signature__angle_brackets_in_email_are_not_supported(void)
 
 void test_commit_signature__create_empties(void)
 {
-   // can not create a signature with empty name or email
+	/* can not create a signature with empty name or email */
 	cl_git_pass(try_build_signature("nulltoken", "emeric.fermas@gmail.com", 1234567890, 60));
 
 	cl_git_fail(try_build_signature("", "emeric.fermas@gmail.com", 1234567890, 60));
@@ -70,19 +70,19 @@ void test_commit_signature__create_empties(void)
 
 void test_commit_signature__create_one_char(void)
 {
-   // creating a one character signature
+	/* creating a one character signature */
 	assert_name_and_email("x", "foo@bar.baz", "x", "foo@bar.baz");
 }
 
 void test_commit_signature__create_two_char(void)
 {
-   // creating a two character signature
+	/* creating a two character signature */
 	assert_name_and_email("xx", "foo@bar.baz", "xx", "foo@bar.baz");
 }
 
 void test_commit_signature__create_zero_char(void)
 {
-   // creating a zero character signature
+	/* creating a zero character signature */
 	git_signature *sign;
 	cl_git_fail(git_signature_new(&sign, "", "x@y.z", 1234567890, 60));
 	cl_assert(sign == NULL);
diff --git a/tests/commit/write.c b/tests/commit/write.c
index 7b0af8c..2ba74ca 100644
--- a/tests/commit/write.c
+++ b/tests/commit/write.c
@@ -15,7 +15,7 @@ static char *head_old;
 static git_reference *head, *branch;
 static git_commit *commit;
 
-// Fixture setup
+/* Fixture setup */
 static git_repository *g_repo;
 void test_commit_write__initialize(void)
 {
@@ -42,7 +42,7 @@ void test_commit_write__cleanup(void)
 }
 
 
-// write a new commit object from memory to disk
+/* write a new commit object from memory to disk */
 void test_commit_write__from_memory(void)
 {
    git_oid tree_id, parent_id, commit_id;
@@ -137,7 +137,7 @@ This is a root commit\n\
 	git_signature_free(committer);
 }
 
-// create a root commit
+/* create a root commit */
 void test_commit_write__root(void)
 {
 	git_oid tree_id, commit_id;
diff --git a/tests/config/write.c b/tests/config/write.c
index cffa54e..521dcb0 100644
--- a/tests/config/write.c
+++ b/tests/config/write.c
@@ -365,7 +365,7 @@ void test_config_write__add_value_at_specific_level(void)
 	int64_t l, expected = +9223372036854775803;
 	git_buf buf = GIT_BUF_INIT;
 
-	// open config15 as global level config file
+	/* open config15 as global level config file */
 	cl_git_pass(git_config_new(&cfg));
 	cl_git_pass(git_config_add_file_ondisk(cfg, "config9",
 		GIT_CONFIG_LEVEL_LOCAL, NULL, 0));
@@ -381,7 +381,7 @@ void test_config_write__add_value_at_specific_level(void)
 	git_config_free(cfg_specific);
 	git_config_free(cfg);
 
-	// open config15 as local level config file
+	/* open config15 as local level config file */
 	cl_git_pass(git_config_open_ondisk(&cfg, "config15"));
 
 	cl_git_pass(git_config_get_int32(&i, cfg, "core.int32global"));
diff --git a/tests/core/filebuf.c b/tests/core/filebuf.c
index 51d8a01..8d1952f 100644
--- a/tests/core/filebuf.c
+++ b/tests/core/filebuf.c
@@ -8,7 +8,7 @@ void test_core_filebuf__0(void)
 	int fd;
 	char test[] = "test", testlock[] = "test.lock";
 
-	fd = p_creat(testlock, 0744); //-V536
+	fd = p_creat(testlock, 0744); /* -V536 */
 
 	cl_must_pass(fd);
 	cl_must_pass(p_close(fd));
diff --git a/tests/core/futils.c b/tests/core/futils.c
index c69c210..fce4848 100644
--- a/tests/core/futils.c
+++ b/tests/core/futils.c
@@ -1,7 +1,7 @@
 #include "clar_libgit2.h"
 #include "fileops.h"
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_core_futils__initialize(void)
 {
 	cl_must_pass(p_mkdir("futils", 0777));
diff --git a/tests/core/vector.c b/tests/core/vector.c
index c2e5d3f..4e6f6fc 100644
--- a/tests/core/vector.c
+++ b/tests/core/vector.c
@@ -18,13 +18,13 @@ void test_core_vector__0(void)
 void test_core_vector__1(void)
 {
 	git_vector x;
-	// make initial capacity exact for our insertions.
+	/* make initial capacity exact for our insertions. */
 	git_vector_init(&x, 3, NULL);
 	git_vector_insert(&x, (void*) 0xabc);
 	git_vector_insert(&x, (void*) 0xdef);
 	git_vector_insert(&x, (void*) 0x123);
 
-	git_vector_remove(&x, 0); // used to read past array bounds.
+	git_vector_remove(&x, 0); /* used to read past array bounds. */
 	git_vector_free(&x);
 }
 
diff --git a/tests/date/rfc2822.c b/tests/date/rfc2822.c
index eda475a..d98c1f0 100644
--- a/tests/date/rfc2822.c
+++ b/tests/date/rfc2822.c
@@ -31,7 +31,7 @@ void test_date_rfc2822__format_rfc2822_negative_offset(void)
 
 void test_date_rfc2822__format_rfc2822_buffer_too_small(void)
 {
-	// "Wed, 10 Apr 2014 08:21:03 +0000"
+	/* "Wed, 10 Apr 2014 08:21:03 +0000" */
 	git_time t = {1397031663 + 86400, 0};
 	char buf[GIT_DATE_RFC2822_SZ-1];
 
diff --git a/tests/describe/t6120.c b/tests/describe/t6120.c
index 6df397e..65e8582 100644
--- a/tests/describe/t6120.c
+++ b/tests/describe/t6120.c
@@ -2,7 +2,7 @@
 #include "describe_helpers.h"
 #include "repository.h"
 
-// Ported from https://github.com/git/git/blob/adfc1857bdb090786fd9d22c1acec39371c76048/t/t6120-describe.sh
+/* Ported from https://github.com/git/git/blob/adfc1857bdb090786fd9d22c1acec39371c76048/t/t6120-describe.sh */
 
 static git_repository *repo;
 
diff --git a/tests/index/conflicts.c b/tests/index/conflicts.c
index cabef88..367d5b5 100644
--- a/tests/index/conflicts.c
+++ b/tests/index/conflicts.c
@@ -9,7 +9,7 @@ static git_index *repo_index;
 #define TEST_REPO_PATH "mergedrepo"
 #define TEST_INDEX_PATH TEST_REPO_PATH "/.git/index"
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_index_conflicts__initialize(void)
 {
 	repo = cl_git_sandbox_init("mergedrepo");
diff --git a/tests/index/names.c b/tests/index/names.c
index 5fa4b4e..11d2c41 100644
--- a/tests/index/names.c
+++ b/tests/index/names.c
@@ -10,7 +10,7 @@ static git_index *repo_index;
 #define TEST_REPO_PATH "mergedrepo"
 #define TEST_INDEX_PATH TEST_REPO_PATH "/.git/index"
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_index_names__initialize(void)
 {
 	repo = cl_git_sandbox_init("mergedrepo");
diff --git a/tests/index/nsec.c b/tests/index/nsec.c
index a20e3ea..dee1509 100644
--- a/tests/index/nsec.c
+++ b/tests/index/nsec.c
@@ -9,7 +9,7 @@ static git_index *repo_index;
 
 #define TEST_REPO_PATH "nsecs"
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_index_nsec__initialize(void)
 {
 	repo = cl_git_sandbox_init("nsecs");
diff --git a/tests/index/reuc.c b/tests/index/reuc.c
index 134f499..1489ed1 100644
--- a/tests/index/reuc.c
+++ b/tests/index/reuc.c
@@ -18,7 +18,7 @@ static git_index *repo_index;
 #define TWO_OUR_OID "8f3c06cff9a83757cec40c80bc9bf31a2582bde9"
 #define TWO_THEIR_OID "887b153b165d32409c70163e0f734c090f12f673"
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_index_reuc__initialize(void)
 {
 	repo = cl_git_sandbox_init("mergedrepo");
diff --git a/tests/index/stage.c b/tests/index/stage.c
index 58dc1fb..cdfe3a8 100644
--- a/tests/index/stage.c
+++ b/tests/index/stage.c
@@ -8,7 +8,7 @@ static git_index *repo_index;
 #define TEST_REPO_PATH "mergedrepo"
 #define TEST_INDEX_PATH TEST_REPO_PATH "/.git/index"
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_index_stage__initialize(void)
 {
 	repo = cl_git_sandbox_init("mergedrepo");
diff --git a/tests/merge/files.c b/tests/merge/files.c
index 6f5a1fd..27c9636 100644
--- a/tests/merge/files.c
+++ b/tests/merge/files.c
@@ -15,7 +15,7 @@
 static git_repository *repo;
 static git_index *repo_index;
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_merge_files__initialize(void)
 {
 	git_config *cfg;
diff --git a/tests/merge/trees/automerge.c b/tests/merge/trees/automerge.c
index 67f2cf7..e16b829 100644
--- a/tests/merge/trees/automerge.c
+++ b/tests/merge/trees/automerge.c
@@ -55,7 +55,7 @@ static git_repository *repo;
 	  "", \
 	  "5c3b68a71fc4fa5d362fd3875e53137c6a5ab7a5" }
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_merge_trees_automerge__initialize(void)
 {
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
diff --git a/tests/merge/trees/modeconflict.c b/tests/merge/trees/modeconflict.c
index d858b8f..e85e340 100644
--- a/tests/merge/trees/modeconflict.c
+++ b/tests/merge/trees/modeconflict.c
@@ -13,7 +13,7 @@ static git_repository *repo;
 #define DF_SIDE1_BRANCH		"df_side1"
 #define DF_SIDE2_BRANCH		"df_side2"
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_merge_trees_modeconflict__initialize(void)
 {
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
diff --git a/tests/merge/trees/renames.c b/tests/merge/trees/renames.c
index 853bf2f..fbcfd2d 100644
--- a/tests/merge/trees/renames.c
+++ b/tests/merge/trees/renames.c
@@ -13,7 +13,7 @@ static git_repository *repo;
 #define BRANCH_RENAME_OURS					"rename_conflict_ours"
 #define BRANCH_RENAME_THEIRS				"rename_conflict_theirs"
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_merge_trees_renames__initialize(void)
 {
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
diff --git a/tests/merge/trees/trivial.c b/tests/merge/trees/trivial.c
index c7f8d24..4a82556 100644
--- a/tests/merge/trees/trivial.c
+++ b/tests/merge/trees/trivial.c
@@ -13,7 +13,7 @@ static git_repository *repo;
 #define TEST_INDEX_PATH TEST_REPO_PATH "/.git/index"
 
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_merge_trees_trivial__initialize(void)
 {
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
diff --git a/tests/merge/trees/whitespace.c b/tests/merge/trees/whitespace.c
index b99583c..fdb1125 100644
--- a/tests/merge/trees/whitespace.c
+++ b/tests/merge/trees/whitespace.c
@@ -16,7 +16,7 @@ static git_repository *repo;
 #define BRANCH_A_CHANGE  "branch_a_change"
 #define BRANCH_B_CHANGE  "branch_b_change"
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_merge_trees_whitespace__initialize(void)
 {
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
diff --git a/tests/merge/workdir/analysis.c b/tests/merge/workdir/analysis.c
index 84885c4..f87fc58 100644
--- a/tests/merge/workdir/analysis.c
+++ b/tests/merge/workdir/analysis.c
@@ -24,7 +24,7 @@ static git_index *repo_index;
 #define NOFASTFORWARD_ID		"7cb63eed597130ba4abb87b3e544b85021905520"
 
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_merge_workdir_analysis__initialize(void)
 {
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
diff --git a/tests/merge/workdir/renames.c b/tests/merge/workdir/renames.c
index fabcda2..a8ee59a 100644
--- a/tests/merge/workdir/renames.c
+++ b/tests/merge/workdir/renames.c
@@ -14,7 +14,7 @@ static git_repository *repo;
 #define BRANCH_RENAME_OURS					"rename_conflict_ours"
 #define BRANCH_RENAME_THEIRS				"rename_conflict_theirs"
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_merge_workdir_renames__initialize(void)
 {
 	git_config *cfg;
diff --git a/tests/merge/workdir/setup.c b/tests/merge/workdir/setup.c
index 92524e2..3a8f9d9 100644
--- a/tests/merge/workdir/setup.c
+++ b/tests/merge/workdir/setup.c
@@ -31,7 +31,7 @@ static git_index *repo_index;
 #define OCTO5_BRANCH		"octo5"
 #define OCTO5_OID			"e4f618a2c3ed0669308735727df5ebf2447f022f"
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_merge_workdir_setup__initialize(void)
 {
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
diff --git a/tests/merge/workdir/simple.c b/tests/merge/workdir/simple.c
index 32b2062..cff1a57 100644
--- a/tests/merge/workdir/simple.c
+++ b/tests/merge/workdir/simple.c
@@ -73,7 +73,7 @@ static git_index *repo_index;
 	  "5c3b68a71fc4fa5d362fd3875e53137c6a5ab7a5" }
 
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_merge_workdir_simple__initialize(void)
 {
 	git_config *cfg;
diff --git a/tests/merge/workdir/submodules.c b/tests/merge/workdir/submodules.c
index c4cc188..35280e6 100644
--- a/tests/merge/workdir/submodules.c
+++ b/tests/merge/workdir/submodules.c
@@ -16,7 +16,7 @@ static git_repository *repo;
 
 #define TEST_INDEX_PATH TEST_REPO_PATH "/.git/index"
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_merge_workdir_submodules__initialize(void)
 {
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
diff --git a/tests/merge/workdir/trivial.c b/tests/merge/workdir/trivial.c
index 85cce49..39d1ddc 100644
--- a/tests/merge/workdir/trivial.c
+++ b/tests/merge/workdir/trivial.c
@@ -14,7 +14,7 @@ static git_index *repo_index;
 #define TEST_INDEX_PATH TEST_REPO_PATH "/.git/index"
 
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_merge_workdir_trivial__initialize(void)
 {
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
diff --git a/tests/network/refspecs.c b/tests/network/refspecs.c
index 15d3624..1a65fd2 100644
--- a/tests/network/refspecs.c
+++ b/tests/network/refspecs.c
@@ -18,7 +18,7 @@ static void assert_refspec(unsigned int direction, const char *input, bool is_ex
 
 void test_network_refspecs__parsing(void)
 {
-	// Ported from https://github.com/git/git/blob/abd2bde78bd994166900290434a2048e660dabed/t/t5511-refspec.sh
+	/* Ported from https://github.com/git/git/blob/abd2bde78bd994166900290434a2048e660dabed/t/t5511-refspec.sh */
 
 	assert_refspec(GIT_DIRECTION_PUSH, "", false);
 	assert_refspec(GIT_DIRECTION_PUSH, ":", true);
@@ -40,8 +40,8 @@ void test_network_refspecs__parsing(void)
 	 * code.  They will be caught downstream anyway, but we may want to
 	 * have tighter check later...
 	 */
-	//assert_refspec(GIT_DIRECTION_PUSH, "refs/heads/master::refs/remotes/frotz/xyzzy", false);
-	//assert_refspec(GIT_DIRECTION_PUSH, "refs/heads/maste :refs/remotes/frotz/xyzzy", false);
+	/*assert_refspec(GIT_DIRECTION_PUSH, "refs/heads/master::refs/remotes/frotz/xyzzy", false); */
+	/*assert_refspec(GIT_DIRECTION_PUSH, "refs/heads/maste :refs/remotes/frotz/xyzzy", false); */
 
 	assert_refspec(GIT_DIRECTION_FETCH, "refs/heads/*:refs/remotes/frotz/*", true);
 	assert_refspec(GIT_DIRECTION_FETCH, "refs/heads/*:refs/remotes/frotz", false);
diff --git a/tests/object/lookupbypath.c b/tests/object/lookupbypath.c
index 13cd6a1..15e79f6 100644
--- a/tests/object/lookupbypath.c
+++ b/tests/object/lookupbypath.c
@@ -42,7 +42,7 @@ void test_object_lookupbypath__errors(void)
 {
 	cl_assert_equal_i(GIT_EINVALIDSPEC,
 			git_object_lookup_bypath(&g_actualobject, (git_object*)g_root_tree,
-				"subdir/subdir_test2.txt", GIT_OBJ_TREE)); // It's not a tree
+				"subdir/subdir_test2.txt", GIT_OBJ_TREE)); /* It's not a tree */
 	cl_assert_equal_i(GIT_ENOTFOUND,
 			git_object_lookup_bypath(&g_actualobject, (git_object*)g_root_tree,
 				"file/doesnt/exist", GIT_OBJ_ANY));
diff --git a/tests/object/message.c b/tests/object/message.c
index 519ce5f..bc00534 100644
--- a/tests/object/message.c
+++ b/tests/object/message.c
@@ -14,8 +14,8 @@ static void assert_message_prettifying(char *expected_output, char *input, int s
 
 #define t40 "A quick brown fox jumps over the lazy do"
 #define s40 "                                        "
-#define sss s40 s40 s40 s40 s40 s40 s40 s40 s40 s40 // # 400
-#define ttt t40 t40 t40 t40 t40 t40 t40 t40 t40 t40 // # 400
+#define sss s40 s40 s40 s40 s40 s40 s40 s40 s40 s40 /* # 400 */
+#define ttt t40 t40 t40 t40 t40 t40 t40 t40 t40 t40 /* # 400 */
 
 /* Ported from git.git */
 /* see https://github.com/git/git/blob/master/t/t0030-stripspace.sh */
diff --git a/tests/object/raw/write.c b/tests/object/raw/write.c
index 273f08f..c7270e2 100644
--- a/tests/object/raw/write.c
+++ b/tests/object/raw/write.c
@@ -16,7 +16,7 @@ void test_body(object_data *d, git_rawobj *o);
 
 
 
-// Helpers
+/* Helpers */
 static void remove_object_files(object_data *d)
 {
    cl_git_pass(p_unlink(d->file));
@@ -57,7 +57,7 @@ static void make_odb_dir(void)
 }
 
 
-// Standard test form
+/* Standard test form */
 void test_body(object_data *d, git_rawobj *o) 
 {
    git_odb *db;
diff --git a/tests/object/tag/list.c b/tests/object/tag/list.c
index 6d5a243..b8d507f 100644
--- a/tests/object/tag/list.c
+++ b/tests/object/tag/list.c
@@ -13,7 +13,7 @@ struct pattern_match_t
 	const char* expected_results[MAX_USED_TAGS];
 };
 
-// Helpers
+/* Helpers */
 static void ensure_tag_pattern_match(git_repository *repo,
 									 const struct pattern_match_t* data)
 {
@@ -34,7 +34,7 @@ static void ensure_tag_pattern_match(git_repository *repo,
 		goto exit;
 	}
 
-	// we have to be prepared that tags come in any order.
+	/* we have to be prepared that tags come in any order. */
 	for (i = 0; i < tag_list.count; i++)
 	{
 		for (j = 0; j < data->expected_matches; j++)
@@ -54,7 +54,7 @@ exit:
 	cl_git_pass(error);
 }
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_object_tag_list__initialize(void)
 {
 	g_repo = cl_git_sandbox_init("testrepo");
@@ -67,7 +67,7 @@ void test_object_tag_list__cleanup(void)
 
 void test_object_tag_list__list_all(void)
 {
-	// list all tag names from the repository
+	/* list all tag names from the repository */
 	git_strarray tag_list;
 
 	cl_git_pass(git_tag_list(&tag_list, g_repo));
@@ -78,37 +78,39 @@ void test_object_tag_list__list_all(void)
 }
 
 static const struct pattern_match_t matches[] = {
-	// All tags, including a packed one and two namespaced ones.
+	/* All tags, including a packed one and two namespaced ones. */
 	{ "", 6, { "e90810b", "point_to_blob", "test", "packed-tag", "foo/bar", "foo/foo/bar" } },
 
-	// beginning with
+	/* beginning with */
 	{ "t*", 1, { "test" } },
 
-	// ending with
+	/* ending with */
 	{ "*b", 2, { "e90810b", "point_to_blob" } },
 
-	// exact match
+	/* exact match */
 	{ "e", 0 },
 	{ "e90810b", 1, { "e90810b" } },
 
-	// either or
+	/* either or */
 	{ "e90810[ab]", 1, { "e90810b" } },
 
-	// glob in the middle
+	/* glob in the middle */
 	{ "foo/*/bar", 1, { "foo/foo/bar" } },
 
-	// The matching of '*' is based on plain string matching analog to the regular expression ".*"
-	// => a '/' in the tag name has no special meaning.
-	// Compare to `git tag -l "*bar"`
+	/*
+	 * The matching of '*' is based on plain string matching analog to the regular expression ".*"
+	 * => a '/' in the tag name has no special meaning.
+	 * Compare to `git tag -l "*bar"`
+	 */
 	{ "*bar", 2, { "foo/bar", "foo/foo/bar" } },
 
-	// End of list
+	/* End of list */
 	{ NULL }
 };
 
 void test_object_tag_list__list_by_pattern(void)
 {
-	// list all tag names from the repository matching a specified pattern
+	/* list all tag names from the repository matching a specified pattern */
 	size_t i = 0;
 	while (matches[i].pattern)
 		ensure_tag_pattern_match(g_repo, &matches[i++]);
diff --git a/tests/object/tag/read.c b/tests/object/tag/read.c
index 8f28afd..e28056e 100644
--- a/tests/object/tag/read.c
+++ b/tests/object/tag/read.c
@@ -13,7 +13,7 @@ static const char *taggerless = "4a23e2e65ad4e31c4c9db7dc746650bfad082679";
 
 static git_repository *g_repo;
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_object_tag_read__initialize(void)
 {
 	g_repo = cl_git_sandbox_init("testrepo");
@@ -27,7 +27,7 @@ void test_object_tag_read__cleanup(void)
 
 void test_object_tag_read__parse(void)
 {
-	// read and parse a tag from the repository
+	/* read and parse a tag from the repository */
 	git_tag *tag1, *tag2;
 	git_commit *commit;
 	git_oid id1, id2, id_commit;
@@ -58,13 +58,13 @@ void test_object_tag_read__parse(void)
 
 void test_object_tag_read__parse_without_tagger(void)
 {
-	// read and parse a tag without a tagger field
+	/* read and parse a tag without a tagger field */
 	git_repository *bad_tag_repo;
 	git_tag *bad_tag;
 	git_commit *commit;
 	git_oid id, id_commit;
 
-	// TODO: This is a little messy
+	/* TODO: This is a little messy */
 	cl_git_pass(git_repository_open(&bad_tag_repo, cl_fixture("bad_tag.git")));
 
 	git_oid_fromstr(&id, bad_tag_id);
@@ -90,13 +90,13 @@ void test_object_tag_read__parse_without_tagger(void)
 
 void test_object_tag_read__parse_without_message(void)
 {
-	// read and parse a tag without a message field
+	/* read and parse a tag without a message field */
 	git_repository *short_tag_repo;
 	git_tag *short_tag;
 	git_commit *commit;
 	git_oid id, id_commit;
 
-	// TODO: This is a little messy
+	/* TODO: This is a little messy */
 	cl_git_pass(git_repository_open(&short_tag_repo, cl_fixture("short_tag.git")));
 
 	git_oid_fromstr(&id, short_tag_id);
diff --git a/tests/object/tag/write.c b/tests/object/tag/write.c
index 68e4b6c..4c50801 100644
--- a/tests/object/tag/write.c
+++ b/tests/object/tag/write.c
@@ -9,7 +9,7 @@ static const char *tagged_commit = "e90810b8df3e80c413d903f631643c716887138d";
 
 static git_repository *g_repo;
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_object_tag_write__initialize(void)
 {
    g_repo = cl_git_sandbox_init("testrepo");
@@ -22,7 +22,7 @@ void test_object_tag_write__cleanup(void)
 
 void test_object_tag_write__basic(void)
 {
-   // write a tag to the repository and read it again
+	/* write a tag to the repository and read it again */
 	git_tag *tag;
 	git_oid target_id, tag_id;
 	git_signature *tagger;
@@ -67,7 +67,7 @@ void test_object_tag_write__basic(void)
 
 void test_object_tag_write__overwrite(void)
 {
-   // Attempt to write a tag bearing the same name than an already existing tag
+	/* Attempt to write a tag bearing the same name than an already existing tag */
 	git_oid target_id, tag_id;
 	git_signature *tagger;
 	git_object *target;
@@ -93,7 +93,7 @@ void test_object_tag_write__overwrite(void)
 
 void test_object_tag_write__replace(void)
 {
-   // Replace an already existing tag
+	/* Replace an already existing tag */
 	git_oid target_id, tag_id, old_tag_id;
 	git_signature *tagger;
 	git_reference *ref_tag;
@@ -130,7 +130,7 @@ void test_object_tag_write__replace(void)
 
 void test_object_tag_write__lightweight(void)
 {
-   // write a lightweight tag to the repository and read it again
+	/* write a lightweight tag to the repository and read it again */
 	git_oid target_id, object_id;
 	git_reference *ref_tag;
 	git_object *target;
@@ -159,7 +159,7 @@ void test_object_tag_write__lightweight(void)
 
 void test_object_tag_write__lightweight_over_existing(void)
 {
-   // Attempt to write a lightweight tag bearing the same name than an already existing tag
+	/* Attempt to write a lightweight tag bearing the same name than an already existing tag */
 	git_oid target_id, object_id, existing_object_id;
 	git_object *target;
 
@@ -181,7 +181,7 @@ void test_object_tag_write__lightweight_over_existing(void)
 
 void test_object_tag_write__delete(void)
 {
-   // Delete an already existing tag
+	/* Delete an already existing tag */
 	git_reference *ref_tag;
 
 	cl_git_pass(git_tag_delete(g_repo, "e90810b"));
diff --git a/tests/object/tree/read.c b/tests/object/tree/read.c
index 59a809b..1d3a913 100644
--- a/tests/object/tree/read.c
+++ b/tests/object/tree/read.c
@@ -6,7 +6,7 @@ static const char *tree_oid = "1810dff58d8a660512d4832e740f692884338ccd";
 
 static git_repository *g_repo;
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_object_tree_read__initialize(void)
 {
    g_repo = cl_git_sandbox_init("testrepo");
@@ -21,7 +21,7 @@ void test_object_tree_read__cleanup(void)
 
 void test_object_tree_read__loaded(void)
 {
-   // acces randomly the entries on a loaded tree
+	/* acces randomly the entries on a loaded tree */
 	git_oid id;
 	git_tree *tree;
 
@@ -42,7 +42,7 @@ void test_object_tree_read__loaded(void)
 
 void test_object_tree_read__two(void)
 {
-   // read a tree from the repository
+	/* read a tree from the repository */
 	git_oid id;
 	git_tree *tree;
 	const git_tree_entry *entry;
diff --git a/tests/rebase/abort.c b/tests/rebase/abort.c
index d8891fb..a83c529 100644
--- a/tests/rebase/abort.c
+++ b/tests/rebase/abort.c
@@ -8,7 +8,7 @@
 
 static git_repository *repo;
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_rebase_abort__initialize(void)
 {
 	repo = cl_git_sandbox_init("rebase");
diff --git a/tests/rebase/inmemory.c b/tests/rebase/inmemory.c
index 367d6b3..040a81b 100644
--- a/tests/rebase/inmemory.c
+++ b/tests/rebase/inmemory.c
@@ -7,7 +7,7 @@
 static git_repository *repo;
 static git_signature *signature;
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_rebase_inmemory__initialize(void)
 {
 	repo = cl_git_sandbox_init("rebase");
diff --git a/tests/rebase/iterator.c b/tests/rebase/iterator.c
index db57b0a..49a6012 100644
--- a/tests/rebase/iterator.c
+++ b/tests/rebase/iterator.c
@@ -8,7 +8,7 @@ static git_repository *repo;
 static git_index *_index;
 static git_signature *signature;
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_rebase_iterator__initialize(void)
 {
 	repo = cl_git_sandbox_init("rebase");
diff --git a/tests/rebase/merge.c b/tests/rebase/merge.c
index 7b2d687..8305937 100644
--- a/tests/rebase/merge.c
+++ b/tests/rebase/merge.c
@@ -19,7 +19,7 @@ static void set_core_autocrlf_to(git_repository *repo, bool value)
 	git_config_free(cfg);
 }
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_rebase_merge__initialize(void)
 {
 	repo = cl_git_sandbox_init("rebase");
diff --git a/tests/rebase/setup.c b/tests/rebase/setup.c
index b07a83a..f002945 100644
--- a/tests/rebase/setup.c
+++ b/tests/rebase/setup.c
@@ -8,7 +8,7 @@ static git_repository *repo;
 static git_index *_index;
 static git_signature *signature;
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_rebase_setup__initialize(void)
 {
 	repo = cl_git_sandbox_init("rebase");
diff --git a/tests/rebase/submodule.c b/tests/rebase/submodule.c
index f71b94f..5aa9ceb 100644
--- a/tests/rebase/submodule.c
+++ b/tests/rebase/submodule.c
@@ -10,7 +10,7 @@
 static git_repository *repo;
 static git_signature *signature;
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_rebase_submodule__initialize(void)
 {
 	git_index *index;
diff --git a/tests/refs/delete.c b/tests/refs/delete.c
index 8cad316..4cc78aa 100644
--- a/tests/refs/delete.c
+++ b/tests/refs/delete.c
@@ -27,7 +27,7 @@ void test_refs_delete__cleanup(void)
 
 void test_refs_delete__packed_loose(void)
 {
-   // deleting a ref which is both packed and loose should remove both tracks in the filesystem
+	/* deleting a ref which is both packed and loose should remove both tracks in the filesystem */
 	git_reference *looked_up_ref, *another_looked_up_ref;
 	git_buf temp_path = GIT_BUF_INIT;
 
@@ -57,7 +57,7 @@ void test_refs_delete__packed_loose(void)
 
 void test_refs_delete__packed_only(void)
 {
-   // can delete a just packed reference
+	/* can delete a just packed reference */
 	git_reference *ref;
 	git_refdb *refdb;
 	git_oid id;
diff --git a/tests/refs/list.c b/tests/refs/list.c
index 97461fd..3e8c82c 100644
--- a/tests/refs/list.c
+++ b/tests/refs/list.c
@@ -22,7 +22,7 @@ void test_refs_list__cleanup(void)
 
 void test_refs_list__all(void)
 {
-   // try to list all the references in our test repo
+	/* try to list all the references in our test repo */
 	git_strarray ref_list;
 
 	cl_git_pass(git_reference_list(&ref_list, g_repo));
diff --git a/tests/refs/normalize.c b/tests/refs/normalize.c
index f9c525e..c692eda 100644
--- a/tests/refs/normalize.c
+++ b/tests/refs/normalize.c
@@ -4,7 +4,7 @@
 #include "git2/reflog.h"
 #include "reflog.h"
 
-// Helpers
+/* Helpers */
 static void ensure_refname_normalized(
 	unsigned int flags,
 	const char *input_refname,
@@ -149,7 +149,7 @@ void test_refs_normalize__symbolic(void)
  
 void test_refs_normalize__jgit_suite(void)
 {
-	// tests borrowed from JGit
+	/* tests borrowed from JGit */
 
 /* EmptyString */
 	ensure_refname_invalid(
@@ -316,9 +316,10 @@ void test_refs_normalize__jgit_suite(void)
 	ensure_refname_normalized(
 		GIT_REF_FORMAT_ALLOW_ONELEVEL, "refs/heads/}", "refs/heads/}");
 
-	// This is valid on UNIX, but not on Windows
-	// hence we make in invalid due to non-portability
-	//
+	/*
+	 * This is valid on UNIX, but not on Windows
+	 * hence we make in invalid due to non-portability
+	 */
 	ensure_refname_invalid(
 		GIT_REF_FORMAT_ALLOW_ONELEVEL, "refs/heads/\\");
 
diff --git a/tests/refs/overwrite.c b/tests/refs/overwrite.c
index 5aea2a7..2e499b7 100644
--- a/tests/refs/overwrite.c
+++ b/tests/refs/overwrite.c
@@ -23,7 +23,7 @@ void test_refs_overwrite__cleanup(void)
 
 void test_refs_overwrite__symbolic(void)
 {
-   // Overwrite an existing symbolic reference
+	/* Overwrite an existing symbolic reference */
 	git_reference *ref, *branch_ref;
 
 	/* The target needds to exist and we need to check the name has changed */
@@ -53,7 +53,7 @@ void test_refs_overwrite__symbolic(void)
 
 void test_refs_overwrite__object_id(void)
 {
-   // Overwrite an existing object id reference
+	/* Overwrite an existing object id reference */
 	git_reference *ref;
 	git_oid id;
 
@@ -85,7 +85,7 @@ void test_refs_overwrite__object_id(void)
 
 void test_refs_overwrite__object_id_with_symbolic(void)
 {
-   // Overwrite an existing object id reference with a symbolic one
+	/* Overwrite an existing object id reference with a symbolic one */
 	git_reference *ref;
 	git_oid id;
 
@@ -110,7 +110,7 @@ void test_refs_overwrite__object_id_with_symbolic(void)
 
 void test_refs_overwrite__symbolic_with_object_id(void)
 {
-   // Overwrite an existing symbolic reference with an object id one
+	/* Overwrite an existing symbolic reference with an object id one */
 	git_reference *ref;
 	git_oid id;
 
diff --git a/tests/refs/read.c b/tests/refs/read.c
index c00b016..3c7a0a1 100644
--- a/tests/refs/read.c
+++ b/tests/refs/read.c
@@ -28,7 +28,7 @@ void test_refs_read__cleanup(void)
 
 void test_refs_read__loose_tag(void)
 {
-   // lookup a loose tag reference
+	/* lookup a loose tag reference */
 	git_reference *reference;
 	git_object *object;
 	git_buf ref_name_from_tag_name = GIT_BUF_INIT;
@@ -54,7 +54,7 @@ void test_refs_read__loose_tag(void)
 
 void test_refs_read__nonexisting_tag(void)
 {
-   // lookup a loose tag reference that doesn't exist
+	/* lookup a loose tag reference that doesn't exist */
 	git_reference *reference;
 
 	cl_git_fail(git_reference_lookup(&reference, g_repo, non_existing_tag_ref_name));
@@ -65,7 +65,7 @@ void test_refs_read__nonexisting_tag(void)
 
 void test_refs_read__symbolic(void)
 {
-   // lookup a symbolic reference
+	/* lookup a symbolic reference */
 	git_reference *reference, *resolved_ref;
 	git_object *object;
 	git_oid id;
@@ -93,7 +93,7 @@ void test_refs_read__symbolic(void)
 
 void test_refs_read__nested_symbolic(void)
 {
-   // lookup a nested symbolic reference
+	/* lookup a nested symbolic reference */
 	git_reference *reference, *resolved_ref;
 	git_object *object;
 	git_oid id;
@@ -121,7 +121,7 @@ void test_refs_read__nested_symbolic(void)
 
 void test_refs_read__head_then_master(void)
 {
-   // lookup the HEAD and resolve the master branch
+	/* lookup the HEAD and resolve the master branch */
 	git_reference *reference, *resolved_ref, *comp_base_ref;
 
 	cl_git_pass(git_reference_lookup(&reference, g_repo, head_tracker_sym_ref_name));
@@ -145,7 +145,7 @@ void test_refs_read__head_then_master(void)
 
 void test_refs_read__master_then_head(void)
 {
-   // lookup the master branch and then the HEAD
+	/* lookup the master branch and then the HEAD */
 	git_reference *reference, *master_ref, *resolved_ref;
 
 	cl_git_pass(git_reference_lookup(&master_ref, g_repo, current_head_target));
@@ -162,7 +162,7 @@ void test_refs_read__master_then_head(void)
 
 void test_refs_read__packed(void)
 {
-   // lookup a packed reference
+	/* lookup a packed reference */
 	git_reference *reference;
 	git_object *object;
 
@@ -182,7 +182,7 @@ void test_refs_read__packed(void)
 
 void test_refs_read__loose_first(void)
 {
-   // assure that a loose reference is looked up before a packed reference
+	/* assure that a loose reference is looked up before a packed reference */
 	git_reference *reference;
 
 	cl_git_pass(git_reference_lookup(&reference, g_repo, packed_head_name));
diff --git a/tests/refs/reflog/reflog.c b/tests/refs/reflog/reflog.c
index a448463..ec251da 100644
--- a/tests/refs/reflog/reflog.c
+++ b/tests/refs/reflog/reflog.c
@@ -11,7 +11,7 @@ static const char *current_master_tip = "a65fedf39aefe402d3bb6e24df4d4f5fe454775
 static git_repository *g_repo;
 
 
-// helpers
+/* helpers */
 static void assert_signature(const git_signature *expected, const git_signature *actual)
 {
 	cl_assert(actual);
@@ -22,15 +22,15 @@ static void assert_signature(const git_signature *expected, const git_signature 
 }
 
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_refs_reflog_reflog__initialize(void)
 {
-   g_repo = cl_git_sandbox_init("testrepo.git");
+	g_repo = cl_git_sandbox_init("testrepo.git");
 }
 
 void test_refs_reflog_reflog__cleanup(void)
 {
-   cl_git_sandbox_cleanup();
+	cl_git_sandbox_cleanup();
 }
 
 static void assert_appends(const git_signature *committer, const git_oid *oid)
diff --git a/tests/refs/rename.c b/tests/refs/rename.c
index e3e5148..6ec8f65 100644
--- a/tests/refs/rename.c
+++ b/tests/refs/rename.c
@@ -34,7 +34,7 @@ void test_refs_rename__cleanup(void)
 
 void test_refs_rename__loose(void)
 {
-	// rename a loose reference
+	/* rename a loose reference */
 	git_reference *looked_up_ref, *new_ref, *another_looked_up_ref;
 	git_buf temp_path = GIT_BUF_INIT;
 	const char *new_name = "refs/tags/Nemo/knows/refs.kung-fu";
@@ -76,7 +76,7 @@ void test_refs_rename__loose(void)
 
 void test_refs_rename__packed(void)
 {
-	// rename a packed reference (should make it loose)
+	/* rename a packed reference (should make it loose) */
 	git_reference *looked_up_ref, *new_ref, *another_looked_up_ref;
 	git_buf temp_path = GIT_BUF_INIT;
 	const char *brand_new_name = "refs/heads/brand_new_name";
@@ -118,7 +118,7 @@ void test_refs_rename__packed(void)
 
 void test_refs_rename__packed_doesnt_pack_others(void)
 {
-	// renaming a packed reference does not pack another reference which happens to be in both loose and pack state
+	/* renaming a packed reference does not pack another reference which happens to be in both loose and pack state */
 	git_reference *looked_up_ref, *another_looked_up_ref, *renamed_ref;
 	git_buf temp_path = GIT_BUF_INIT;
 	const char *brand_new_name = "refs/heads/brand_new_name";
@@ -160,7 +160,7 @@ void test_refs_rename__packed_doesnt_pack_others(void)
 
 void test_refs_rename__name_collision(void)
 {
-	// can not rename a reference with the name of an existing reference
+	/* can not rename a reference with the name of an existing reference */
 	git_reference *looked_up_ref, *renamed_ref;
 
 	/* An existing reference... */
@@ -179,7 +179,7 @@ void test_refs_rename__name_collision(void)
 
 void test_refs_rename__invalid_name(void)
 {
-	// can not rename a reference with an invalid name
+	/* can not rename a reference with an invalid name */
 	git_reference *looked_up_ref, *renamed_ref;
 
 	/* An existing oid reference... */
@@ -205,7 +205,7 @@ void test_refs_rename__invalid_name(void)
 
 void test_refs_rename__force_loose_packed(void)
 {
-	// can force-rename a packed reference with the name of an existing loose and packed reference
+	/* can force-rename a packed reference with the name of an existing loose and packed reference */
 	git_reference *looked_up_ref, *renamed_ref;
 	git_oid oid;
 
@@ -230,7 +230,7 @@ void test_refs_rename__force_loose_packed(void)
 
 void test_refs_rename__force_loose(void)
 {
-	// can force-rename a loose reference with the name of an existing loose reference
+	/* can force-rename a loose reference with the name of an existing loose reference */
 	git_reference *looked_up_ref, *renamed_ref;
 	git_oid oid;
 
@@ -258,7 +258,7 @@ void test_refs_rename__force_loose(void)
 
 void test_refs_rename__overwrite(void)
 {
-	// can not overwrite name of existing reference
+	/* can not overwrite name of existing reference */
 	git_reference *ref, *ref_one, *ref_one_new, *ref_two;
 	git_refdb *refdb;
 	git_oid id;
@@ -292,7 +292,7 @@ void test_refs_rename__overwrite(void)
 
 void test_refs_rename__prefix(void)
 {
-	// can be renamed to a new name prefixed with the old name
+	/* can be renamed to a new name prefixed with the old name */
 	git_reference *ref, *ref_two, *looked_up_ref, *renamed_ref;
 	git_oid id;
 
@@ -325,7 +325,7 @@ void test_refs_rename__prefix(void)
 
 void test_refs_rename__move_up(void)
 {
-	// can move a reference to a upper reference hierarchy
+	/* can move a reference to a upper reference hierarchy */
 	git_reference *ref, *ref_two, *looked_up_ref, *renamed_ref;
 	git_oid id;
 
diff --git a/tests/refs/setter.c b/tests/refs/setter.c
index 2b42ff2..03c2146 100644
--- a/tests/refs/setter.c
+++ b/tests/refs/setter.c
@@ -65,7 +65,7 @@ void test_refs_setter__update_symbolic(void)
 
 void test_refs_setter__cant_update_direct_with_symbolic(void)
 {
-	// Overwrite an existing object id reference with a symbolic one
+	/* Overwrite an existing object id reference with a symbolic one */
 	git_reference *ref, *new;
 	git_oid id;
 
@@ -80,7 +80,7 @@ void test_refs_setter__cant_update_direct_with_symbolic(void)
 
 void test_refs_setter__cant_update_symbolic_with_direct(void)
 {
-	// Overwrite an existing symbolic reference with an object id one
+	/* Overwrite an existing symbolic reference with an object id one */
 	git_reference *ref, *new;
 	git_oid id;
 
diff --git a/tests/repo/discover.c b/tests/repo/discover.c
index b13c97b..cc61c71 100644
--- a/tests/repo/discover.c
+++ b/tests/repo/discover.c
@@ -58,7 +58,7 @@ static void write_file(const char *path, const char *content)
 	cl_git_pass(error);
 }
 
-//no check is performed on ceiling_dirs length, so be sure it's long enough
+/*no check is performed on ceiling_dirs length, so be sure it's long enough */
 static void append_ceiling_dir(git_buf *ceiling_dirs, const char *path)
 {
 	git_buf pretty_path = GIT_BUF_INIT;
diff --git a/tests/revert/bare.c b/tests/revert/bare.c
index 206c86d..fda2b82 100644
--- a/tests/revert/bare.c
+++ b/tests/revert/bare.c
@@ -11,7 +11,7 @@
 
 static git_repository *repo;
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_revert_bare__initialize(void)
 {
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
diff --git a/tests/revert/workdir.c b/tests/revert/workdir.c
index 8604735..53bb0e4 100644
--- a/tests/revert/workdir.c
+++ b/tests/revert/workdir.c
@@ -12,7 +12,7 @@
 static git_repository *repo;
 static git_index *repo_index;
 
-// Fixture setup and teardown
+/* Fixture setup and teardown */
 void test_revert_workdir__initialize(void)
 {
 	git_config *cfg;
diff --git a/tests/stash/apply.c b/tests/stash/apply.c
index 986eba0..16cb140 100644
--- a/tests/stash/apply.c
+++ b/tests/stash/apply.c
@@ -422,7 +422,7 @@ void test_stash_apply__uses_reflog_like_indices_1(void)
 	cl_git_pass(git_stash_save(&oid, repo, signature, NULL, GIT_STASH_INCLUDE_UNTRACKED));
 	assert_status(repo, "untracked", GIT_ENOTFOUND);
 
-	// stash@{1} is the oldest (first) stash we made
+	/* stash@{1} is the oldest (first) stash we made */
 	cl_git_pass(git_stash_apply(repo, 1, NULL));
 	cl_assert_equal_i(git_index_has_conflicts(repo_index), 0);
 	assert_status(repo, "what", GIT_STATUS_WT_MODIFIED);
@@ -441,7 +441,7 @@ void test_stash_apply__uses_reflog_like_indices_2(void)
 	cl_git_pass(git_stash_save(&oid, repo, signature, NULL, GIT_STASH_INCLUDE_UNTRACKED));
 	assert_status(repo, "untracked", GIT_ENOTFOUND);
 
-	// stash@{0} is the newest stash we made immediately above
+	/* stash@{0} is the newest stash we made immediately above */
 	cl_git_pass(git_stash_apply(repo, 0, NULL));
 
 	cl_assert_equal_i(git_index_has_conflicts(repo_index), 0);
diff --git a/tests/status/status_data.h b/tests/status/status_data.h
index 8ad4235..09b9827 100644
--- a/tests/status/status_data.h
+++ b/tests/status/status_data.h
@@ -1,6 +1,6 @@
 #include "status_helpers.h"
 
-// A utf-8 string with 83 characters, but 249 bytes.
+/* A utf-8 string with 83 characters, but 249 bytes. */
 static const char *longname = "\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97\xe5\x8f\x97";
 
 
diff --git a/tests/status/worktree.c b/tests/status/worktree.c
index bb9f8ec..7abc703 100644
--- a/tests/status/worktree.c
+++ b/tests/status/worktree.c
@@ -260,7 +260,7 @@ void test_status_worktree__within_subdir(void)
 	pathsArray.strings = paths;
 	opts.pathspec = pathsArray;
 
-	// We committed zzz_new_dir/new_file above. It shouldn't be reported.
+	/* We committed zzz_new_dir/new_file above. It shouldn't be reported. */
 	cl_git_pass(
 		git_status_foreach_ext(repo, &opts, cb_status__normal, &counts)
 	);
@@ -957,7 +957,7 @@ void test_status_worktree__long_filenames(void)
 	git_status_options opts = GIT_STATUS_OPTIONS_INIT;
 	status_entry_counts counts = {0};
 
-	// Create directory with amazingly long filename
+	/* Create directory with amazingly long filename */
 	sprintf(path, "empty_standard_repo/%s", longname);
 	cl_git_pass(git_futils_mkdir_r(path, 0777));
 	sprintf(path, "empty_standard_repo/%s/foo", longname);
diff --git a/tests/threads/basic.c b/tests/threads/basic.c
index af60490..9ce740c 100644
--- a/tests/threads/basic.c
+++ b/tests/threads/basic.c
@@ -19,7 +19,7 @@ void test_threads_basic__cleanup(void)
 
 void test_threads_basic__cache(void)
 {
-	// run several threads polling the cache at the same time
+	/* run several threads polling the cache at the same time */
 	cl_assert(1 == 1);
 }
 
diff --git a/tests/worktree/config.c b/tests/worktree/config.c
index 3ab317b..81dcfe1 100644
--- a/tests/worktree/config.c
+++ b/tests/worktree/config.c
@@ -36,8 +36,10 @@ void test_worktree_config__set(void)
 	cl_git_pass(git_config_set_int32(cfg, "core.dummy", 5));
 	git_config_free(cfg);
 
-	// reopen to verify configuration has been set in the
-	// common dir
+	/*
+	 * reopen to verify configuration has been set in the
+	 * common dir
+	 */
 	cl_git_pass(git_repository_config(&cfg, fixture.repo));
 	cl_git_pass(git_config_get_int32(&val, cfg, "core.dummy"));
 	cl_assert_equal_i(val, 5);