Now that last_wait_event is entirely handled in nat/windows-nat.c, it
can be made static.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* nat/windows-nat.h (last_wait_event): Don't declare.
(wait_for_debug_event): Update comment.
* nat/windows-nat.c (last_wait_event): Now static.