* configure.in: Remove NEWVFORK default.

* configure: Regenerate.
* dcrt0.cc: Conditionalize vfork stuff throughout.
* dtable.cc: Ditto.
* perthread.h: Ditto.
* pipe.cc (fhandler_pipe::close): Ditto.
* spawn.cc (spawnve): Ditto.
* syscalls.cc (setsid): Ditto.
* exceptions.cc (sigpacket::process): Use macro to refer to vfork pid.
* debug.cc (verify_handle): Define new function.
* debug.h (VerifyHandle): Define new macro.
(verify_handle): Declare new function
* fhandler.cc (fhandler_base::dup): Verify that dup'ed handle is not supposed
to be in use.
(fhandler_base::set_inheritance): Ditto.
(fhandler_base::fork_fixup): Ditto.
* fhandler_socket.cc (fhandler_socket::dup): Ditto.
* fhandler_tty.cc (fhandler_tty_slave::open): Ditto.
* net.cc (set_socket_inheritance): Ditto.
* pinfo.cc (pinfo_fixup_after_exec): Ditto.
* sigproc.cc (proc_subproc): Ditto.
(sig_send): Ditto.
* spawn.cc (spawn_guts): Ditto.
* thread.cc (pthread::init_mainthread): Ditto.
* pipe.cc (fhandler_pipe::close): Close read_state with ForceCloseHandle since
it was protected.
(fhandler_pipe::fixup_after_exec): Protect read_state handle.
(fhandler_pipe::dup): Correctly close open handles on error condition.  Verify
that dup'ed handle is not supposed to be in use.
(fhandler_pipe::create): Protect read_state.

winsup/cygwin/cygheap.cc

@@ -178,6 +178,9 @@ init_cygheap::close_ctty ()
   debug_printf ("closing cygheap->ctty %p", cygheap->ctty);
   int usecount = cygheap->ctty->usecount;
   cygheap->ctty->close ();
+#ifndef NEWVFORK
+  cygheap->ctty = NULL;
+#else  // FIXME: This code ain't right
   if (cygheap->ctty_on_hold == cygheap->ctty)
     cygheap->ctty_on_hold = NULL;
   if (usecount == 1)
@@ -185,6 +188,7 @@ init_cygheap::close_ctty ()
       cygheap->ctty = NULL;
       debug_printf ("setting cygheap->ctty to NULL");
     }
+#endif
 }
 
 #define pagetrunc(x) ((void *) (((DWORD) (x)) & ~(4096 - 1)))