* cygheap.cc (cygheap_init): Born again function.

(_cmalloc): Reorganize to accomodate muto locking.
(_cfree): Use muto lock to avoid multi-thread problems.
* cygheap.h (incygheap): Just use cygheap_max to find upper cygwin heap bounds.
* dcrt0.cc (dll_crt0_1): Reinstitute cygheap_init call.
* path.cc (getcwd): Just return cwdstuff::get result, allowing correct handling
of negative length.
(cwdstuff::get): Malloc a buffer if one is not available.

winsup/cygwin/sync.cc

@@ -116,7 +116,7 @@ muto::release ()
   if (!--visits)
     {
       tid = 0;		/* We were the last unlocker. */
-      InterlockedExchange (&sync, 0); /* Reset trigger. */
+      (void) InterlockedExchange (&sync, 0); /* Reset trigger. */
       /* This thread had incremented waiters but had never decremented it.
 	 Decrement it now.  If it is >= 0 then there are possibly other
 	 threads waiting for the lock, so trigger bruteforce. */