* DevNotes: Add entry cgf-000003.

* cygheap.h (init_cygheap::pid_handle): Delete.
* dcrt0.cc (child_info_spawn::handle_spawn): Keep parent open if we have
execed.
* pinfo.cc (pinfo::thisproc): Remove pid_handle manipulations.
(pinfo::init): Don't consider a reaped process to be available.
* spawn.cc (child_info_spawn::worker): Remove pid_handle manipulations.  Make
wr_proc_pipe and parent noninheritable when starting a program which doesn't
use the Cygwin DLL.  Conditionally reset wr_proc_pipe to inheritable if
CreateProcess fails.  Inject wr_proc_pipe handle into non-Cygwin process.
Consider a non-cygwin process to be 'synced'.

winsup/cygwin/cygheap.h

@@ -390,7 +390,6 @@ struct init_cygheap: public mini_cygheap
   struct _cygtls **threadlist;
   size_t sthreads;
   pid_t pid;			/* my pid */
-  HANDLE pid_handle;		/* handle for my pid */
   struct {			/* Equivalent to using LIST_HEAD. */
     struct inode_t *lh_first;
   } inode_list;			/* Global inode pointer for adv. locking. */