Add "git_path()" and "head_ref()" helper functions.
"git_path()" returns a static pathname pointer into the git directory
using a printf-like format specifier.
"head_ref()" works like "for_each_ref()", except for just the HEAD.
diff --git a/refs.h b/refs.h
index a79cb13..2625596 100644
--- a/refs.h
+++ b/refs.h
@@ -5,6 +5,7 @@
* Calls the specified function for each ref file until it returns nonzero,
* and returns the value
*/
+extern int head_ref(int (*fn)(const char *path, const unsigned char *sha1));
extern int for_each_ref(int (*fn)(const char *path, const unsigned char *sha1));
/** Reads the refs file specified into sha1 **/
