fix errors in printf-style format strings

There were many places where the arguments to a printf-like function did
not match the format string.  Mostly, these were a missing 'l' flag, but
there were three exceptions:

- In ui-stats.c, a size_t argument must be printed.  C99 has the "%zu"
  flag for this purpose, but not all compilers support this.  Therefore,
  we mimic what git does - use a NO_C99_FORMAT Makefile variable.

- In ui-stats.c, cgit_print_error() was called with a pointer instead of
  a character.

- In ui-log.c, the "columns" argument was never used.

Signed-off-by: Mark Lodato <lodatom@gmail.com>

cgit.c

@@ -610,7 +610,7 @@ static void process_cached_repolist(const char *path)
 	hash = hash_str(path);
 	if (ctx.cfg.project_list)
 		hash += hash_str(ctx.cfg.project_list);
-	cached_rc = xstrdup(fmt("%s/rc-%8x", ctx.cfg.cache_root, hash));
+	cached_rc = xstrdup(fmt("%s/rc-%8lx", ctx.cfg.cache_root, hash));
 
 	if (stat(cached_rc, &st)) {
 		/* Nothing is cached, we need to scan without forking. And