* dcrt0.cc (child_info_fork::alloc_stack_hard_way): Change sense of guard test.

Increase size of stack reserved and increase size before the current stack
pointer.  Use pointers when doing arithmetic.
(dll_crt0_1): Initialize exception handler when we notice we're the child of a
fork from non-main thread.
* fork.cc (frok::parent): Make argument volatile.
(frok::child): Ditto.
(lock_signals): New class.
(lock_pthread): Ditto.
(hold_everhthing): Ditto.
(frok::parent): Move atforkprepare and atforkparent to lock_pthread class.
(fork): Make ischild boolean.  Use hold_everything variable within limited
scope to set various mutexes in such a way as to avoid deadlocks.
* thread.h (pthread_mutex::tid): New variable, active when debugging for
tracking thread id of owner.
(pthread_mutex::set_owner): Set tid when debugging.
* thread.cc (pthread_mutex::pthread_mutex): Clear tid.
(pthread_mutex::_unlock): Ditto when unlocking.
(pthread_mutex::fixup_after_fork): Set tid to special value after forking since
owner is unknown.

winsup/cygwin/thread.h

@@ -1,9 +1,6 @@
 /* thread.h: Locking and threading module definitions
 
-   Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2007 Red Hat, Inc.
-
-   Written by Marco Fuykschot <marco@ddi.nl>
-   Major update 2001 Robert Collins <rbtcollins@hotmail.com>
+   Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007 Red Hat, Inc.
 
 This file is part of Cygwin.
 
@@ -45,7 +42,8 @@ void ReleaseResourceLock (int, int, const char *)
   __attribute__ ((regparm (3)));
 }
 
-DWORD cancelable_wait (HANDLE, DWORD, const cw_cancel_action = cw_cancel_self, const enum cw_sig_wait = cw_sig_nosig)
+DWORD cancelable_wait (HANDLE, DWORD, const cw_cancel_action = cw_cancel_self,
+		       const enum cw_sig_wait = cw_sig_nosig)
   __attribute__ ((regparm (3)));
 
 class fast_mutex
@@ -298,6 +296,9 @@ public:
   unsigned int recursion_counter;
   LONG condwaits;
   pthread_t owner;
+#ifdef DEBUGGING
+  DWORD tid;		/* the thread id of the owner */
+#endif
   int type;
   int pshared;
 
@@ -328,6 +329,9 @@ public:
   {
     recursion_counter = 1;
     owner = self;
+#ifdef DEBUGGING
+    tid = GetCurrentThreadId ();
+#endif
   }
 
   int lock_recursive ()