[php-src] Issue #7846: curl and other native libraries block pcntl async signal propagation

Issue: https://github.com/php/php-src/issues/7846 Comment Author: cmb69 The RFC states: "Registered signal handlers are going to be called at some points during user script execution without any overhead." If you're calling an internal function which does not call back to the user script, no signal handling is supposed to happen. At least that is how I understand it. I'm leaving that to someone with a POSIX background to confirm (in which case this is a doc issue), or to refute.