fix return

vlib/os/os.v

@@ -761,11 +761,13 @@ pub fn execute_or_exit(cmd string) Result {
 // quoted path - return a quoted version of the path, depending on the platform.
 pub fn quoted_path(path string) string {
 	$if windows {
+		mut quoted_path := ''
 		if path.ends_with(path_separator) {
-			return '"${path + path_separator}"'
+			quoted_path = '"${path + path_separator}"'
 		} else {
-			return '"$path"'
+			quoted_path = '"$path"'
 		}
+		return quoted_path
 	} $else {
 		return "'$path'"
 	}