* frame.h (FRAME_SAMPLE_VISIBILITY): Make sure frame is marked as

* frame.h (FRAME_SAMPLE_VISIBILITY): Make sure frame is marked as
	garbaged whenever it goes from invisible to visible.
	* dispextern.h (frame_garbaged): Move extern declaration from here...
	* frame.h (frame_garbaged): ... to here.  The FRAME_SAMPLE_VISIBILITY
	macro uses it now, and this seems to be just as modular.  Make a
	new page, just for this and message_buf_print.
	(struct frame): Doc fix for the `visible' field.
	* process.c: #include "frame.h" instead of "dispextern.h"; the
	only thing we care about from it is the frame_garbaged
	declaration.
	* ymakefile: Note dependency change.