* exceptions.cc (sig_handle_tty_stop): Move setting of PID_STOPPED to earlier
in interrupt.
((interrupt_setup): i.e., here.
(sig_handle): Don't queue multiple SIGSTOPS.
* fhandler.h (bg_check_types): Enumerate return value of bg_check for clarity.
* signal.cc (kill_pgrp): Minor cleanup.
* fhandler_termios.cc (fhandler_termios::bg_check): Use enumerated type for
function return. Don't raise signal if a signal is already queued.
* fhandler_console.cc (fhandler_console::read): Use enumerated return type for
bg_check.
* select.cc: Ditto, throughout.
* read.cc: Ditto, throughout.
* termios.cc: Ditto, throughout.
(_read): YA interrupt detect simplification.
* wait.cc (wait4): Ditto.
a7cde2b98a