* assert.cc (__assert): Call debugger on assertion failure if debugging.

* dcrt0.cc (dll_crt0_1): Just wait for signal thread to go live rather than
going through the overhead of invoking it.
* fork.cc (fork_child): Ditto.
* exceptions.cc (signal_fixup_after_fork): Call sigproc_init here.
* sigproc.cc (proc_can_be_signalled): Assume that the signal thread is live.
(sig_dispatch): Ditto.
(sig_send): Ditto.
(wait_for_sigthread): Renamed from "wait_for_me".  Assume that wait_sig_inited
has been set and that this function is only called from the main thread.
* winsup.h (wait_for_sigthread): Declare new function.

winsup/cygwin/assert.cc

@@ -46,6 +46,9 @@ __assert (const char *file, int line, const char *failedexpr)
 		    failedexpr, file, line);
     }
 
+#ifdef DEBUGGING
+  try_to_debug ();
+#endif
   abort ();	// FIXME: Someday this should work.
 
   /* NOTREACHED */