sha1: add missing header guards
diff --git a/src/sha1.h b/src/sha1.h
index 93a244d..f0a16f2 100644
--- a/src/sha1.h
+++ b/src/sha1.h
@@ -5,6 +5,9 @@
* a Linking Exception. For full terms see the included COPYING file.
*/
+#ifndef INCLUDE_sha1_h__
+#define INCLUDE_sha1_h__
+
typedef struct {
unsigned long long size;
unsigned int H[5];
@@ -19,3 +22,5 @@ void git__blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx);
#define SHA1_Init git__blk_SHA1_Init
#define SHA1_Update git__blk_SHA1_Update
#define SHA1_Final git__blk_SHA1_Final
+
+#endif