Fix detection of unknown gcc function attributes
- LP: #1882279
- https://github.com/php/php-src/pull/8483
As discussed in [1], and old, buggy gcc macro have been hindering the php build configuration step, resulting in a binary which cannot make use of some performance improvements introduced to php upstream.
The observe performance difference between the upstream binaries shipped in docker.io/php showed these upstream binaries may perform some operations up to 10x faster than the downstream versions in x86_64-v{2,3,4} machines.
The patch proposed here fixes the embedded gcc macro so the binary can be built leveraging the gcc function attributes that provide such performance boosts.
[1] https://bugs.launchpad.net/ubuntu/+source/php8.1/+bug/1882279/comments/9