Perform whitespace cleanup throughout.

Perform whitespace cleanup throughout.
* dcrt0.cc (signal_shift_subtract): Eliminate ancient backwards compatibility.
(check_sanity_and_sync): Ditto.
* winsup.h (SIGTOMASK): Ditto.  Just use constant in signal calculation.
* include/cygwin/version: Remove backwards signal mask compatibility define.
* path.cc (symlink_info::check_sysfile): Cosmetic change.
* registry.cc (get_registry_hive_path): Remove unneeded variable.
* exceptions.cc (handle_sigsuspend): Eliminate thread signal mask and use
either main sigmask or current thread sigmask.
(set_process_mask): Ditto.
(sighold): Ditto.
(sigrelse): Ditto.
(sigset): Ditto.
(set_process_mask_delta): Ditto.
(_cygtls::call_signal_handler): Ditto.
* fhandler_process.cc (format_process_status): Ditto.
* fhandler_termios.cc (fhandler_termios::bg_check): Ditto.
* pinfo.h (class pinfo): Ditto.
* select.cc (pselect): Ditto.
* signal.cc (sigprocmask): Ditto.
(abort): Ditto.
(sigpause): Ditto.
(sigsend): Ditto.
(wait_sig): Ditto.
* thread.h (pthread::parent_tls): New member.
* thread.cc (pthread::pthread): Record parent_tls here.
(pthread::thread_init_wrapper): Initialize sigmask from parent thread.