* 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/debug.cc

@@ -87,7 +87,7 @@ thread_stub (VOID *arg)
   exception_list except_entry;
 
   /* Give up our slot in the start_buf array */
-  InterlockedExchange (&((thread_start *) arg)->notavail, 0);
+  (void) InterlockedExchange (&((thread_start *) arg)->notavail, 0);
 
   /* Initialize this thread's ability to respond to things like
      SIGSEGV or SIGFPE. */