* exceptions.cc (set_signal_mask): Remove useless debugging output.

* exceptions.cc (set_signal_mask): Remove useless debugging output.
* fhandler.cc (fhandler_base::write): Ditto.
(fhandler_base_overlapped::close): Cancel any ongoing I/O before closing.
* syscalls.cc (write): Default to always reporting all writes in strace output
via syscall_printf.
* wait.cc (wait4): Fix debugging output.  Use standard syscall leaver output.