thodg/libgit2

diff --git a/fuzzers/CMakeLists.txt b/fuzzers/CMakeLists.txt
index 59eca24..6d042d9 100644
--- a/fuzzers/CMakeLists.txt
+++ b/fuzzers/CMakeLists.txt
@@ -1,3 +1,8 @@
+# Ensure that MinGW provides the correct header files.
+IF (WIN32 AND NOT CYGWIN)
+	ADD_DEFINITIONS(-DWIN32 -D_WIN32_WINNT=0x0600)
+ENDIF()
+
 LINK_DIRECTORIES(${LIBGIT2_LIBDIRS})
 INCLUDE_DIRECTORIES(${LIBGIT2_INCLUDES})
 INCLUDE_DIRECTORIES(SYSTEM ${LIBGIT2_SYSTEM_INCLUDES})
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index a97e8fe..4589d81 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -14,6 +14,11 @@ ADD_DEFINITIONS(-D_FILE_OFFSET_BITS=64)
 # Ensure that we do not use deprecated functions internally
 ADD_DEFINITIONS(-DGIT_DEPRECATE_HARD)
 
+# Ensure that MinGW provides the correct header files.
+IF (WIN32 AND NOT CYGWIN)
+	ADD_DEFINITIONS(-DWIN32 -D_WIN32_WINNT=0x0600)
+ENDIF()
+
 INCLUDE_DIRECTORIES(${CLAR_PATH} ${libgit2_BINARY_DIR}/src)
 FILE(GLOB_RECURSE SRC_TEST ${CLAR_PATH}/*/*.c ${CLAR_PATH}/*/*.h)
 SET(SRC_CLAR "main.c" "clar_libgit2.c" "clar_libgit2_trace.c" "clar_libgit2_timer.c" "clar.c")