Merge branch 'jk/maint-add-empty' into maint

* jk/maint-add-empty:
  add: don't complain when adding empty project root

builtin-add.c

@@ -61,7 +61,7 @@ static void prune_directory(struct dir_struct *dir, const char **pathspec, int p
 	fill_pathspec_matches(pathspec, seen, specs);
 
 	for (i = 0; i < specs; i++) {
-		if (!seen[i] && !file_exists(pathspec[i]))
+		if (!seen[i] && pathspec[i][0] && !file_exists(pathspec[i]))
 			die("pathspec '%s' did not match any files",
 					pathspec[i]);
 	}