git-compat-util: drop mempcpy compat code

There are no callers of this left, as the last one was
dropped in the previous patch. And there are not likely to
be new ones, as the function has been around since 2010
without gaining any new callers.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-compat-util.h

@@ -681,7 +681,6 @@ extern int git_vsnprintf(char *str, size_t maxsize,
 #ifdef __GLIBC_PREREQ
 #if __GLIBC_PREREQ(2, 1)
 #define HAVE_STRCHRNUL
-#define HAVE_MEMPCPY
 #endif
 #endif
 
@@ -695,14 +694,6 @@ static inline char *gitstrchrnul(const char *s, int c)
 }
 #endif
 
-#ifndef HAVE_MEMPCPY
-#define mempcpy gitmempcpy
-static inline void *gitmempcpy(void *dest, const void *src, size_t n)
-{
-	return (char *)memcpy(dest, src, n) + n;
-}
-#endif
-
 #ifdef NO_INET_PTON
 int inet_pton(int af, const char *src, void *dst);
 #endif