Autotools: Move auto_cflags marker to PHP_INIT_BUILD_SYSTEM

[petk]

The "hacky" auto_cflags variable is otherwise set only for the Oracle Developer Studio compiler (which is at this point also non-usable) and perhaps might be removed in the future but this is for now moved to the PHP_INIT_BUILD_SYSTEM for consistent settings between the php-src build and phpize.

The PHP_INIT_BUILD_SYSTEM is now also called sooner in phpize to match the php-src build.

[petk]

I've rechecked this. Merging into master branch.

[andypost]

Please elaborate, is CFLAGS from environment has preference on passing as argument?

[petk]

Please elaborate, is CFLAGS from environment has preference on passing as argument?

Yes. When setting CFLAGS variable in command line ./configure CFLAGS=... will override default Autoconf's CFLAGS value. So it needs to be set to something sensible for the build. One of the issues with Autoconf not appending some user defined CFLAGS. Trying to resolve this via #12050 at some point and using the CFLAGS_EXTRA or something like that. Perhaps PHP_CFLAGS...

[andypost]

Thank you 👍

[petk]

@andypost Autoconf actually sets this CFLAGS to very simple values. There are mostly only -g -O2 when GNU C compatible compiler is used (gcc, clang...), or to -g for other compilers. Basically, you can set it to anything on your build as long as some suitable optimization level -O... is used for the production. Yes, we probably should look into this a bit more how to do that a bit more automatically in PHP build system directly but for now it's like this.