* child_info.h (cchildren): New struct.

(child_info_spawn::nchildren): Rename from nprocs.
(child_info_spawn::children): Change type to cchildren for more bookkeeping
possibilities.
(child_info_spawn::child_info_spawn): Clear nchildren.
(child_info_spawn::record_children): Declare new function.
(child_info_spawn::reattach_children): Ditto.
* dcrt0.cc (child_info_spawn::handle_spawn): Call reattach_children to gather
list of processes we are potentially waiting for.
* pinfo.h (pinfo::pinfo): Make sure that rd_proc_pipe is always cleared.
(pinfo::reattach): New function.
* sigproc.cc: Move pinfo.h earlier so that it can be used in sigproc.h.
(get_proc_lock): Don't bother with a lock during DLL initialization.
(proc_subproc): Handle PROC_REATTACH_CHILD.
(proc_terminate): Orphan children only when we are not an execed process or
when the pid is about to be occupied by a non-cygwin process.
(child_info_spawn::record_children): Define new function.
(child_info_spawn::reattach_children): Ditto.
* sigproc.h (procstuff): Define PROC_REATTACH_CHILD and renumber other
elements.
* spawn.cc (spawn_guts): Record any to-be-waited-for subprocesses if about to
exec a cygwin process.
* sigproc.cc (sig_send): Fix harmless transposition of fifth and six arguments
to DuplicateHandle().
(child_info::child_info): Ditto.
* globals.cc (hExeced): Make NO_COPY.

winsup/cygwin/dcrt0.cc

@@ -625,6 +625,12 @@ child_info_spawn::handle_spawn ()
     cygheap->fdtab.move_fd (__stdout, 1);
   cygheap->user.groups.clear_supp ();
 
+  /* If we're execing we may have "inherited" a list of children forked by the
+     previous process executing under this pid.  Reattach them here so that we
+     can wait for them.  */
+  if (type == _PROC_EXEC)
+    reattach_children ();
+
   ready (true);
 
   /* Need to do this after debug_fixup_after_fork_exec or DEBUGGING handling of