* window.c (minibuffer_window): Accept an optional FRAME argument;

* window.c (minibuffer_window): Accept an optional FRAME argument;
	if specified, return the minibuffer used by that frame.

	* window.c (Fset_window_configuration): Don't signal an error
	if the frame size saved in the window configuration doesn't
	match the frame's current size; instead, temporarily resize
	the frame while installing the window configuration.  This is
	important because using the minibuffer saves and restores the
	current window configuration, and you don't want to signal an
	error just because the user resized the frame while using the
	minibuffer.