* cygheap.cc (init_cheap): Just use any old address for the cygwin heap.

* exceptions.cc (signal_exit): Don't terminate the main thread.  Just try to
exit in this thread really quickly.
* signal.cc (kill_pgrp): Fix typo which caused pinfo structure to be assigned
incorrectly.

winsup/cygwin/signal.cc

@@ -185,7 +185,7 @@ kill_pgrp (pid_t pid, int sig)
   winpids pids;
   for (unsigned i = 0; i < pids.npids; i++)
     {
-      pinfo p = pids[i];
+      pinfo p (pids[i]);
 
       if (!proc_exists (p))
 	continue;