* src/xdisp.c (message2, message2_nolog): Remove functions.

* src/xdisp.c (message2, message2_nolog): Remove functions.
(message3, message3_nolog): Extract nbytes and multibyteness directly
from the string.  Change all callers.
(message3_nolog): Don't set message_enable_multibyte since set_message
will reset it anyway.
(message1, message1_nolog): Use message3.
(vmessage): Use a stack allocated buffer rather than f->message_buf.
(with_echo_area_buffer): Remove last two arguments.  Update all callers.
(set_message): Drop all but the second arg, which has to be a string.
(set_message_1): Simplify now that we know that a1 is NULL and the
second arg is a string.
* src/frame.h (struct frame): Remove `message_buf' field.
Use glyphs_initialized_p instead.
(FRAME_MESSAGE_BUF): Remove macro.
* src/w16select.c (Fw16_set_clipboard_data): Prefer message3 to message2.
* src/lisp.h (message2, message2_nolog): Remove declarations.
(message3, message3_nolog): Update declarations.
* src/keyboard.c (read_char_minibuf_menu_text)
(read_char_minibuf_menu_width): Remove vars.
(read_char_minibuf_menu_prompt): Rewrite the menu's construction so as
to correctly handle multibyte strings.
* src/frame.c (delete_frame): Don't free message_buf any more.
* src/editfns.c (message_text, message_length): Remove vars.
(Fmessage_box): Don't copy the Lisp string's bytes any longer.
* src/fileio.c (auto_save_error): Use message3 instead of message2.
* src/dispnew.c (adjust_frame_message_buffer): Remove function.