replace xstrdup(git_path(...)) with git_pathdup(...)

It's more efficient to use git_pathdup(), as it skips an
extra copy of the path. And by removing some calls to
git_path(), it makes it easier to audit for dangerous uses.

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

Author: peff

builtin/config.c

@@ -599,8 +599,9 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		if (given_config_source.blob)
 			die("editing blobs is not supported");
 		git_config(git_default_config, NULL);
-		config_file = xstrdup(given_config_source.file ?
-				      given_config_source.file : git_path("config"));
+		config_file = given_config_source.file ?
+				xstrdup(given_config_source.file) :
+				git_pathdup("config");
 		if (use_global_config) {
 			int fd = open(config_file, O_CREAT | O_EXCL | O_WRONLY, 0666);
 			if (fd >= 0) {

fast-import.c

@@ -3203,7 +3203,7 @@ static char* make_fast_import_path(const char *path)
 {
 	if (!relative_marks_paths || is_absolute_path(path))
 		return xstrdup(path);
-	return xstrdup(git_path("info/fast-import/%s", path));
+	return git_pathdup("info/fast-import/%s", path);
 }
 
 static void option_import_marks(const char *marks,