* cygheap.cc (dup_now): Make fatal error a little more informative.

(cygheap_setup_for_child): Detect when default size of shared region is less
than the current size and allocate that much.
(_cbrk): Just return NULL on inability to allocate.
(_cmalloc): Ditto.
* cygheap.h (CYGHEAPSIZE): Change size to reflect newer, tinier fhandler sizes.
* spawn.cc (av::error): New element, reflects potential errno from cmalloc.
(av::~av): Don't free NULL pointers.
(av::replace0_maybe): Detect out-of-memory conditions.
(av::dup_maybe): Ditto.
(av::dup_all): Ditto.
(av::unshift): Ditto.
(spawn_guts): Set errno and return if argv creation ran into problems.
* fhandler.h (fhandler_union): Change member names to something safer.
* fhandler_console.cc (fhandler_console::get_tty_stuff): Always set
fhandler_console::dev_state regardless of whether shared region is initialized.
* cygthread.cc (cygthread::runner): Use ExitThread rather than return
(planning for future).

winsup/cygwin/cygheap.h

@@ -224,7 +224,7 @@ struct init_cygheap
   bool etc_changed ();
 };
 
-#define CYGHEAPSIZE (sizeof (init_cygheap) + (4000 * sizeof (fhandler_union)) + (2 * 65536))
+#define CYGHEAPSIZE (sizeof (init_cygheap) + (16000 * sizeof (fhandler_union)) + (4 * 65536))
 
 extern init_cygheap *cygheap;
 extern void *cygheap_max;