thodg/libgit2

diff --git a/Makefile b/Makefile
index 9aa923b..c7cc7cc 100644
--- a/Makefile
+++ b/Makefile
@@ -3,6 +3,12 @@ all::
 # Define NO_VISIBILITY if your compiler does not support symbol
 # visibility in general (and the -fvisibility switch in particular).
 #
+# Define OPENSSL_SHA1 if you want use the SHA1 routines from the
+# OpenSSL crypto library, rather than the built-in C versions.
+#
+# Define PPC_SHA1 if you want to use the bundled SHA1 routines that
+# are optimized for PowerPC, rather than the built-in C versions.
+#
 
 DOXYGEN = doxygen
 INSTALL = install
@@ -75,8 +81,12 @@ ifdef PPC_SHA1
 	EXTRA_OBJ += src/ppc/sha1ppc.o
 	EXTRA_CFLAGS += -DPPC_SHA1
 else
+ifdef OPENSSL_SHA1
+	EXTRA_CFLAGS += -DOPENSSL_SHA1
+else
 	EXTRA_SRC += src/block-sha1/sha1.c
 endif
+endif
 
 BASIC_CFLAGS := -Isrc
 ifndef NO_VISIBILITY
diff --git a/src/block-sha1/sha1.h b/src/block-sha1/sha1.h
index b864df6..bb2bad2 100644
--- a/src/block-sha1/sha1.h
+++ b/src/block-sha1/sha1.h
@@ -16,7 +16,7 @@ void blk_SHA1_Init(blk_SHA_CTX *ctx);
 void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *dataIn, unsigned long len);
 void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx);
 
-#define git_SHA_CTX	blk_SHA_CTX
-#define git_SHA1_Init	blk_SHA1_Init
-#define git_SHA1_Update	blk_SHA1_Update
-#define git_SHA1_Final	blk_SHA1_Final
+#define SHA_CTX		blk_SHA_CTX
+#define SHA1_Init	blk_SHA1_Init
+#define SHA1_Update	blk_SHA1_Update
+#define SHA1_Final	blk_SHA1_Final
diff --git a/src/hash.c b/src/hash.c
index 784b10b..1ddf7a3 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -28,7 +28,7 @@
 #include "sha1.h"
 
 struct git_hash_ctx {
-	git_SHA_CTX c;
+	SHA_CTX c;
 };
 
 git_hash_ctx *git_hash_new_ctx(void)
@@ -38,7 +38,7 @@ git_hash_ctx *git_hash_new_ctx(void)
 	if (!ctx)
 		return NULL;
 
-	git_SHA1_Init(&ctx->c);
+	SHA1_Init(&ctx->c);
 
 	return ctx;
 }
@@ -51,37 +51,37 @@ void git_hash_free_ctx(git_hash_ctx *ctx)
 void git_hash_init(git_hash_ctx *ctx)
 {
 	assert(ctx);
-	git_SHA1_Init(&ctx->c);
+	SHA1_Init(&ctx->c);
 }
 
 void git_hash_update(git_hash_ctx *ctx, const void *data, size_t len)
 {
 	assert(ctx);
-	git_SHA1_Update(&ctx->c, data, len);
+	SHA1_Update(&ctx->c, data, len);
 }
 
 void git_hash_final(git_oid *out, git_hash_ctx *ctx)
 {
 	assert(ctx);
-	git_SHA1_Final(out->id, &ctx->c);
+	SHA1_Final(out->id, &ctx->c);
 }
 
 void git_hash_buf(git_oid *out, const void *data, size_t len)
 {
-	git_SHA_CTX c;
+	SHA_CTX c;
 
-	git_SHA1_Init(&c);
-	git_SHA1_Update(&c, data, len);
-	git_SHA1_Final(out->id, &c);
+	SHA1_Init(&c);
+	SHA1_Update(&c, data, len);
+	SHA1_Final(out->id, &c);
 }
 
 void git_hash_vec(git_oid *out, git_buf_vec *vec, size_t n)
 {
-	git_SHA_CTX c;
+	SHA_CTX c;
 	size_t i;
 
-	git_SHA1_Init(&c);
+	SHA1_Init(&c);
 	for (i = 0; i < n; i++)
-		git_SHA1_Update(&c, vec[i].data, vec[i].len);
-	git_SHA1_Final(out->id, &c);
+		SHA1_Update(&c, vec[i].data, vec[i].len);
+	SHA1_Final(out->id, &c);
 }
diff --git a/src/ppc/sha1.h b/src/ppc/sha1.h
index c405f73..7095711 100644
--- a/src/ppc/sha1.h
+++ b/src/ppc/sha1.h
@@ -19,7 +19,7 @@ int ppc_SHA1_Init(ppc_SHA_CTX *c);
 int ppc_SHA1_Update(ppc_SHA_CTX *c, const void *p, unsigned long n);
 int ppc_SHA1_Final(unsigned char *hash, ppc_SHA_CTX *c);
 
-#define git_SHA_CTX	ppc_SHA_CTX
-#define git_SHA1_Init	ppc_SHA1_Init
-#define git_SHA1_Update	ppc_SHA1_Update
-#define git_SHA1_Final	ppc_SHA1_Final
+#define SHA_CTX		ppc_SHA_CTX
+#define SHA1_Init	ppc_SHA1_Init
+#define SHA1_Update	ppc_SHA1_Update
+#define SHA1_Final	ppc_SHA1_Final
diff --git a/src/sha1.h b/src/sha1.h
index ac3e846..f4153cc 100644
--- a/src/sha1.h
+++ b/src/sha1.h
@@ -1,8 +1,10 @@
 #ifndef INCLUDE_sha1_h__
 #define INCLUDE_sha1_h__
 
-#ifdef PPC_SHA1
+#if defined(PPC_SHA1)
 # include "ppc/sha1.h"
+#elif defined(OPENSSL_SHA1)
+# include <openssl/sha.h>
 #else
 # include "block-sha1/sha1.h"
 #endif
diff --git a/tests/Makefile b/tests/Makefile
index 6a5c2bc..e5ff267 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -59,6 +59,10 @@ ifdef TEST_COVERAGE
 	EXTRA_LIBS += -O0 -lgcov
 endif
 
+ifdef OPENSSL_SHA1
+	EXTRA_LIBS += $(CRYPTO_LIB)
+endif
+
 BASIC_CFLAGS := -I../src
 
 ALL_CFLAGS = $(CFLAGS) $(BASIC_CFLAGS)