* child_info.h: Bump magic number.

* child_info.h: Bump magic number.
(class child_info): Add an element.
* cygheap.cc (init_cheap): Allocate cygwin heap in shared memory area.
(cygheap_fixup_in_child): Map cygwin heap, passed from parent via shared memory
into correct address.
(cygheap_setup_for_child): New function.
* cygheap.h: Declare new functions.
* dcrt0.cc (dll_crt0_1): Accomodate new cygheap_fixup_in_child arguments.
Avoid protecting subproc_ready unless it is spawn/nowait.
* fork.cc (fork_parent): Use new cygheap_setup_for_child function to setup
cygwin heap info.  Close passed cygheap shared memory handle.
* spawn.cc (spawn_guts): Ditto.  Also, reorganize to avoid synchronization
between parent and child in non-P_OVERLAY case.
* sigproc.cc (wait_sig): Only signal subproc_ready when execing.