Add overloads of for_each_thread/find_thread that filter on pid

It happens often that we want to iterate or find threads restricted to a
given pid.  I think it's worth having an overload to help with this.
Right now there is a single user of each of the find_thread and
for_each_thread overload, but as we replace the usages of find_inferior
with for_each_thread/find_thread, more usages will pop up.

gdb/gdbserver/ChangeLog:

	* gdbthread.h (find_thread, for_each_thread): New functions.
	* inferiors.c (thread_of_pid): Remove.
	(find_any_thread_of_pid): Use find_thread.
	* linux-low.c (num_lwps): Use for_each_thread.

1 files changed, 3 insertions, 12 deletions

diff --git a/gdb/gdbserver/inferiors.c b/gdb/gdbserver/inferiors.c
index 564121f..a0ece4d 100644
--- a/gdb/gdbserver/inferiors.c
+++ b/gdb/gdbserver/inferiors.c
@@ -132,23 +132,14 @@ find_thread_process (const struct process_info *const process)
   return find_any_thread_of_pid (process->pid);
 }
 
-/* Helper for find_any_thread_of_pid.  Returns true if a thread
-   matches a PID.  */
-
-static int
-thread_of_pid (thread_info *entry, void *pid_p)
-{
-  int pid = *(int *) pid_p;
-
-  return (ptid_get_pid (entry->id) == pid);
-}
-
 /* See gdbthread.h.  */
 
 struct thread_info *
 find_any_thread_of_pid (int pid)
 {
-  return find_inferior (&all_threads, thread_of_pid, &pid);
+  return find_thread (pid, [] (thread_info *thread) {
+    return true;
+  });
 }
 
 static void