* 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'.
