$links = preg_replace_callback('{'.self::$DEFINES.'"'.$packageRegex.'"(?P<separator>\s*:\s*)(?&string)}ix', function ($m) use ($package, $constraint) {
$links = preg_replace_callback('{'.self::$DEFINES.'"'.$packageRegex.'"(?P<separator>\s*:\s*)(?&string)}ix', function ($m) use ($existingPackage, $constraint) {