* keyboard.c (read_key_sequence): Removed the
replay_sequence_new_buffer label; replay_sequence should be here
instead.
* keyboard.c (Vlast_event_frame): Arrange for this to exist iff
MULTI_FRAME is defined.
[not MULTI_FRAME] (syms_of_keyboard): Don't DEFVAR Vlast_event_frame.
[not MULTI_FRAME] (read_char): Don't try to set Vlast_event_frame.
[not MULTI_FRAME] (kbd_buffer_store_event): Don't try to set
Vlast_event_frame for quit characters.
[not MULTI_FRAME] (kbd_buffer_get_event): Don't try to generate
switch-frame events.