* fork.cc (fork): Lock the process before forking to prevent things like new

fds from being opened, etc.
* sync.h (lock_process::dont_bother): New function.

winsup/cygwin/sync.h

@@ -50,6 +50,7 @@ class lock_process
   static muto locker;
 public:
   static void init () {locker.init ("lock_process");}
+  void dont_bother () {skip_unlock = true;}
   lock_process (bool exiting = false)
   {
     locker.acquire ();