[php-src] Issue #12273: __builtin_cpu_init configure check relies on void return value

Issue: https://github.com/php/php-src/issues/12273 Author: Freaky ### Description Testing [enabling ifunc support on FreeBSD](https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=274011), alongside having to remove the hardcoded check that disables it I also run into: ``` checking for __builtin_cpu_init... no ``` https://github.com/php/php-src/blob/f6fae19a109a40026239e61e26c0403e7c340efb/build/php.m4#L2735 ```m4 AC_LINK_IFELSE([AC_LANG_PROGRAM([], [[ return __builtin_cpu_init()? 1 : 0; ]])], [ ``` While this does technically appear to return int on gcc, it's documented as void __builtin_cpu_init (void), and indeed returns such on clang. Changing this to: ```m4 AC_LINK_IFELSE([AC_LANG_PROGRAM([], [[ __builtin_cpu_init(); return 1; ]])], [ ``` Results in a successful check and much faster addslashes, base64_encode, etc. ### PHP Version PHP 8.1.23 ### Operating System FreeBSD 13.2-RELEASE