* dcrt0.cc (sigthread::init): Correct overzealous ifdef.

* exceptions.cc (call_handler): Avoid calling sigthread acquire lock.
* sigproc.h (sigthread): Comment out lock for now.
* sync.cc (muto::acquire): Add a minor optimization.

winsup/cygwin/sigproc.h

@@ -38,7 +38,9 @@ struct sigthread
 {
   DWORD id;
   DWORD frame;
+#if 0
   muto *lock;			// FIXME: Use for multi-thread signalling someday
+#endif
   void init (const char *s);
 };