- make_fcontext() never returns NULL.
- Show syscall error info in exception just like zend_alloc does (we also used php_win32_error_*() in Zend).
- MAP_ANON was marked as deprecated or compatibility macro on Linux, It would be better to use MAP_ANONYMOUS first.
- Makes the code consistent with the code of other modules in the kernel.
- adds some comments.
This additional internal fiber API creates and manipulates a Fiber object, allowing any internal function to start, resume, or suspend a fiber. The existing zend_fiber_context API allows custom C-based fiber creation using the bundled switching context, but does not interact with the PHP VM. This API behaves the same as calling Fiber object methods from user code, switching EGs, and triggering the fiber switch observer. In general, the Fiber object methods call these new API methods.
This removes switching to main for fatal errors in fibers in favor of catching any zend_bailout in a fiber and calling zend_bailout again after switching to the previous fiber or {main}.
Checking EG(current_exectue_data) throws into the previous fiber instead of triggering a fatal error during shutdown. A fatal error is triggered only if the throwing destroyed fiber was resumed from {main}.
Previously an exception thrown during fiber destruction resulted in a fatal error, but that exception should be able to be caught (unless we’ve entered shutdown, then still use a fatal error so the error is not hidden).
This is needed by both fibers and opcache (and GH-6903 also uses it),
so make it a common structure that can be used by any functionality
storing warnings/errors.
