[php-src] Issue #9460: pcntl_signal() not included in Embed SAPI

Issue: https://github.com/php/php-src/issues/9460 Author: cayolblake ### Description Basically any code with pcntl_signal() fails with this error. Resulted in this output: ``` PHP Fatal error: Uncaught Error: Call to undefined function pcntl_signal() ``` Inspecting my libphp.so ``` $ strings /opt/remi/php81/root/usr/lib64/libphp-8.1.so | grep pcntl_si pcntl_signal_get_handler ``` While in main PHP binary ``` $ strings /usr/bin/php81 | grep pcntl_si pcntl_signal pcntl_signal_get_handler pcntl_signal_dispatch pcntl_sigprocmask pcntl_sigwaitinfo pcntl_sigtimedwait ``` Is this intentional? If so, why? ### PHP Version 8.1.9 ### Operating System _No response_