* cygwait.h (cancelable_wait): Make extern to avoid always including.

* select.cc (allocfd_set): Try to make a little more efficient.
(cygwin_select): Break into two functions to avoid what seems to be a strange
compiler problem with alloca and sel constructor.
(select): New function.  Always honor return from call_signal_handler.
(select_stuff::wait): Always honor return from call_signal_handler.
* select.h (select_stuff::select_stuff): Use NULL to initialize pointers rather
than 0.

winsup/cygwin/select.h

@@ -97,9 +97,9 @@ public:
 
   select_stuff (): return_on_signal (false), always_ready (false),
   		   windows_used (false), start (0),
-		   device_specific_pipe (0),
-		   device_specific_socket (0),
-		   device_specific_serial (0),
-		   device_specific_mailslot (0) {}
+		   device_specific_pipe (NULL),
+		   device_specific_socket (NULL),
+		   device_specific_serial (NULL),
+		   device_specific_mailslot (NULL) {}
 };
 #endif /* _SELECT_H_ */