Some versions of PHP seem to not like this:
$ sudo arc liberate SCAN Searching for libraries in the current working directory... WORK Updating library: arcanist/ [2021-09-15 15:52:11] EXCEPTION: (XHPASTSyntaxErrorException) linter/StdintLinter.php: XHPAST Parse Error: syntax error, unexpected ')' on line 66 at [<arcanist>/src/moduleutils/PhutilLibraryMapBuilder.php:491] ...