Add '#include "cygwait.h"' throughout, where appropriate.

* DevNotes: Add entry cgf-000012.
* Makefile.in (DLL_OFILES): Add cygwait.o.
* sigproc.h: Remove cygwait definitions.
* cygwait.h: New file.  Define/declare Cygwin waitfor functions.
* cygwait.cc: Ditto.
* exceptions.cc: Include cygwait.h.
(handle_sigsuspend): Accommodate change in cancelable_wait arguments.
(sigpacket::process): Display thread tls in debugging output.
* fhandler.cc (fhandler_base_overlapped::wait_overlapped): Use symbolic names
for signal and cancel return.
* fhandler_console.cc (fhandler_console::read): Ditto.
(fhandler_dev_dsp::Audio_out::waitforspace): Ditto.
fhandler_dev_dsp::Audio_in::waitfordata): Ditto.
* fhandler_fifo.cc (fhandler_fifo::wait): Ditto.
* fhandler_serial.cc (fhandler_serial::raw_read): Ditto.
* fhandler_tty.cc (fhandler_pty_slave::read): Ditto.
* select.cc (cygwin_select): Ditto.
* wait.cc (wait4): Ditto.
* thread.cc (cancelable_wait): Move definition to cygwait.h.
(pthread_cond::wait): Accommodate change in cancelable_wait arguments.
(pthread_mutex::lock): Ditto.
(pthread_spinlock::lock): Ditto.
(pthread::join): Ditto.
(pthread::thread_init_wrapper): Display tls in debugging output.
(semaphore::_timedwait): Ditto.
* thread.h (cw_sig_wait): Move to cygwait.h.
(cw_cancel_action): Delete.
(cancelable_wait): Move declaration to cygwait.h.

winsup/cygwin/DevNotes

@@ -1,3 +1,25 @@
+2012-06-12  cgf-000012
+
+These changes are the preliminary for redoing the way threads wait for
+signals.  The problems are shown by the test case mentioned here:
+
+http://cygwin.com/ml/cygwin/2012-05/msg00434.html
+
+I've known that the signal handling in threads wasn't quite right for
+some time.  I lost all of my thread signal tests in the great "rm -r"
+debacle of a few years ago and have been less than enthusiastic about
+redoing everything (I had PCTS tests and everyting).  But it really is
+time to redo this signal handling to make it more like it is supposed to
+be.
+
+This change should not introduce any new behavior.  Things should
+continue to behave as before.  The major differences are a change in the
+arguments to cancelable_wait and cygwait now uses cancelable_wait and,
+so, the returns from cygwait now mirror cancelable_wait.
+
+The next change will consolidate cygwait and cancelable_wait into one
+cygwait function.
+
 2012-06-02  cgf-000011
 
 The refcnt handling was tricky to get right but I had convinced myself