Some get_last_target_status tweaks

- Make get_last_target_status arguments optional.  A following patch
  will add another argument to get_last_target_status (the event's
  target), and passing nullptr when we don't care for some piece of
  info is handier than creating dummy local variables.

- Declare nullify_last_target_wait_ptid in a header, and remove the
  local extern declaration from linux-fork.c.

gdb/ChangeLog:
2020-01-10  Pedro Alves  <palves@redhat.com>

	* break-catch-sig.c (signal_catchpoint_print_it): Don't pass a
	ptid to get_last_target_status.
	* break-catch-syscall.c (print_it_catch_syscall): Don't pass a
	ptid to get_last_target_status.
	* infcmd.c (continue_command): Don't pass a target_waitstatus to
	get_last_target_status.
	(info_program_command): Don't pass a target_waitstatus to
	get_last_target_status.
	* infrun.c (init_wait_for_inferior): Use
	nullify_last_target_wait_ptid.
	(get_last_target_status): Handle nullptr arguments.
	(nullify_last_target_wait_ptid): Clear target_last_waitstatus.
	(print_stop_event): Don't pass a ptid to get_last_target_status.
	(normal_stop): Don't pass a ptid to get_last_target_status.
	* infrun.h (get_last_target_status, set_last_target_status): Move
	comments here and update.
	(nullify_last_target_wait_ptid): Declare.
	* linux-fork.c (fork_load_infrun_state): Remove local extern
	declaration of nullify_last_target_wait_ptid.
	* linux-nat.c (get_detach_signal): Don't pass a target_waitstatus
	to get_last_target_status.

1 files changed, 1 insertions, 2 deletions

diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 4484fa5..a01839c 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -1315,10 +1315,9 @@ get_detach_signal (struct lwp_info *lp)
 	}
       else if (!target_is_non_stop_p ())
 	{
-	  struct target_waitstatus last;
 	  ptid_t last_ptid;
 
-	  get_last_target_status (&last_ptid, &last);
+	  get_last_target_status (&last_ptid, nullptr);
 
 	  if (lp->ptid.lwp () == last_ptid.lwp ())
 	    signo = tp->suspend.stop_signal;