drop length argument of has_extension

As Fredrik points out the current interface of has_extension() is
potentially confusing.  Its parameters include both a nul-terminated
string and a length-limited string.

This patch drops the length argument, requiring two nul-terminated
strings; all callsites are updated.  I checked that all of them indeed
provide nul-terminated strings.  Filenames need to be nul-terminated
anyway if they are to be passed to open() etc.  The performance penalty
of the additional strlen() is negligible compared to the system calls
which inevitably surround has_extension() calls.

Additionally, change has_extension() to use size_t inside instead of
int, as that is the exact type strlen() returns and memcmp() expects.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-compat-util.h

@@ -139,9 +139,10 @@ static inline ssize_t xwrite(int fd, const void *buf, size_t len)
 	}
 }
 
-static inline int has_extension(const char *filename, int len, const char *ext)
+static inline int has_extension(const char *filename, const char *ext)
 {
-	int extlen = strlen(ext);
+	size_t len = strlen(filename);
+	size_t extlen = strlen(ext);
 	return len > extlen && !memcmp(filename + len - extlen, ext, extlen);
 }