* init.cc (dll_entry): Remove unused extern.

* init.cc (dll_entry): Remove unused extern.
* include/sys/cygwin.h: Remove PID_ZOMBIE.
* pinfo.h: Rename EXITCODE_* defines.
(pinfo::set_exit_state): Remove parameter.
* pinfo.cc (set_exit_state): Remove parameter.  Reverse sense of test so that
exitcode is checked for having been set rather than not having been set.  Set
flag when exitcode has been established.  Don't set PID_STATE here.
(pinfo::init): Remove exitcode initialization.
(pinfo::exit): Reflect change in EXITCODE_* naming.  Set flag when exitcode has
been established.  Reflect change in arguments to set_process_state.
(proc_waiter): Reflect change in arguments to set_process_state.  Set
process_state here and only here.
* fhandler_process.cc (fhandler_process::fill_filebuf): Reflect removal of
PID_ZOMBIE define.
(format_process_stat): Ditto.
(format_process_status): Ditto.
* sigproc.cc (pid_exists): Ditto.
(stopped_or_terminated): Ditto.  Make sure that only low-order 16 bits of
exitcode are used.
* spawn.cc (spawn_guts): Reflect change in EXITCODE_* naming.