* sigproc.cc (mychild): Reimplement as list scan.

* sigproc.cc (mychild): Reimplement as list scan.
(proc_subproc): Don't mess with pinfo if it's myself.
* child_info.h (child_info_types): Label enum for _PROC constants.
(child_info::child_info): New constructor.
(child_info::~child_info): New destructor.
(child_info::sync): Declare new function.
(child_info_fork::child_info_fork): New constructor.
(child_info_spawn::child_info_spawn): Remove old constructor.
(child_info_spawn::child_info_spawn): New constructor.
* dcrt0.cc (dll_crt0_0): Use correct sizeof when doing sanity check on passed
in child_info.  Signal readiness to parent when not forking (and not spawning).
* fork.cc (sync_with_child): Delete.
(resume_child): Remove extra argument.
(sync_with_parent): Use child_info method to sync with parent.
(fork_child): Don't close fork_info->subproc_ready since that is now handled by
the destructor.
(fork_parent): Remove subproc_ready stuff.  Use child_info sync method for
waiting..  Set start time here for child.  Rename "forked" to "child".
(fork): Check ch.subproc_ready for validity here.
* pinfo.h (_pinfo::exec_sendsig): Temp storage for exec stub which may be
staying around to handle non-cygwin captive process.
(_pinfo::exec_dwProcessId): Ditto.
(_pinfo::_lock): Renamed from lock.
(_pinfo::lock): New method.
(_pinfo::unlock): Ditto.
(_pinfo::initialize_lock): Ditto.
* pinfo.cc (set_myself): Use initialize_lock method to initialize myself lock.
Set "exec" fields in _pinfo to zero to indicate that we've started
successfully.  Set start time here when appropriate.
(_pinfo::commune_send): Use pinfo lock/unlock methods.
(proc_waiter): Remove special case for non-cywin processes.  Reinstitute
handling for PID_NOCLDSTOP.
* sigproc.cc (proc_subproc): Set proper EAGAIN errno when process table is
filled.
(sig_send): Use exec_* fields from _pinfo for sending signals if the the _pinfo
sendsig never materializes.
(child_info::child_info): New constructor, renamed from init_child_info.
Zeroes child_info structure and sets appropriate fields in structure based on
chtype.
(child_info::~child_info): New destructor.  Closes subproc_ready if it exists.
(child_info_fork::child_info_fork): New constructor.
(child_info_spawn::child_info_spawn): New constructor.
(child_info::ready): New function.  Signals parent when child is ready.
(child_info::sync): New function.  Wait for child to signal us or process to
die.
(remove_proc): Remove closing of hProcess since this should now be handled
shortly after process creation.
* spawn.cc (spawn_guts): Use child_info_spawn constructor rather than
init_child_info.  Save exec_sendsig and exec_dwProcessId in execing _pinfo.
Rely on child_info constructor to properly set parent_wr_proc_pipe in ciresrv.
Revert to previous determination on whether to start a process in suspended
mode.  Remove reparenting stuff.  Just keep a stub around if starting a
non-cygwin process.