Fix deadlock when receiving SIGCHLD during 'pselect'.
If we receive and handle a SIGCHLD signal for a process while waiting for that process, 'pselect' might never return. Instead, we have to explicitly 'pselect' that the process status has changed. We do this by writing to a pipe in the SIGCHLD handler and having 'wait_reading_process_output' select on it. * src/process.c (child_signal_init): New helper function to create a pipe for SIGCHLD notifications. (child_signal_read, child_signal_notify): New helper functions to read from/write to the child signal pipe. (create_process): Initialize the child signal pipe on first use. (handle_child_signal): Notify waiters that a process status has changed. (wait_reading_process_output): Make sure that we also catch SIGCHLD/process status changes. * test/src/process-tests.el (process-tests/fd-setsize-no-crash/make-process): Remove workaround, which is no longer needed.
Showing with 93 additions and 6 deletions