Merge branch 'js/config-cb'

* js/config-cb:
  Provide git_config with a callback-data parameter

Conflicts:

	builtin-add.c
	builtin-cat-file.c

builtin-checkout.c

@@ -516,7 +516,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	memset(&opts, 0, sizeof(opts));
 	memset(&new, 0, sizeof(new));
 
-	git_config(git_default_config);
+	git_config(git_default_config, NULL);
 
 	opts.track = git_branch_track;