* cygheap.cc (cygheap_init): Eliminate debugging #if.

* fork.cc (fork_parent): Don't issue errors if "somebody" has set the
PID_EXITED flag on a child.  Don't close process handle if it has potentially
already been closed.
* pinfo.cc (winpids::add): Eliminate PID_ALLPIDS handling which was obsoleted
by previous changes.
* spawn.cc (av::fixup): Do win16 detection for .com files.  Make sure that
buffer has been unmapped in all cases.

winsup/cygwin/cygheap.cc

@@ -158,12 +158,7 @@ cygheap_init ()
   cygheap_protect.init ("cygheap_protect");
   if (!cygheap)
     {
-#if 1
       cygheap = (init_cygheap *) memset (_cygheap_start, 0, _cygheap_mid - _cygheap_start);
-#else
-      cygheap = (init_cygheap *) _cygheap_start;
-#endif
-
       cygheap_max = cygheap;
       _csbrk (sizeof (*cygheap));
     }