* fhandler.h: Declare new function. Add extra argument to
process_slave_output.
* fhandler_console.cc (fhandler_console::read): Move read ahead code to new
function.
* fhandler_tty.cc (fhandler_pty_master::process_slave_output): Move common code
here.
(fhandler_tty_slave::read): Understand readahead.
(fhandler_pty_master::read): Move code to process_slave_output.
* select.cc (peek_pipe): Avoid performing certain checks when non-read and on
inappropriate fh types.
(call_handler): Allow signals to be sent even if signalled thread is stopped.
Change order of signal_arrived arming/waiting threads clearing to eliminate a
race.
(reset_signal_arrived): New helper function.
* malloc.cc (malloc_init): Use mutos so that signal handler can keep track of
who owns the lock.
(__malloc_lock): Ditto.
(__malloc_unlock): Ditto.
* sync.h (new_muto): Actually use a muto for the "buffer".
* Makefile.in: Fix a dependency.