[php-src] Issue #7924: Regex pattern modifier u needed with umlaut on Arch, but not Ubuntu, Windows, alpine

Issue: https://github.com/php/php-src/issues/7924 Author: FlyingHelix ### Description The following code: ```php <?php var_dump(preg_match('/^[\p{L}\p{Mn}]{8,128}$/', 'gülitgesWort')); var_dump(preg_match('/^[\p{L}\p{Mn}]{8,128}$/u', 'gülitgesWort')); ``` Resulted in this output on Windows 10, last used was 21h1 with xampp, Ubuntu different Versions, 20.04, 21.04 and 21.10 and the php:alpine docker image : ``` int(1) int(1) ``` and this output on Arch Linux, x86_64, Kernel 5.15.13-zen1-1-zen ``` int(0) int(1) ``` on different PHP versions as well, namely 7.4, 8.0.14, 8.0.12 and 8.1 could be a local issue with my arch distro as well, but i used the same locale from a working Ubuntu setup for example as a test. ### PHP Version PHP 8.0.14 ### Operating System _No response_