* xterm.c (x_wm_set_size_hint): Set the base_width and base_height

* xterm.c (x_wm_set_size_hint): Set the base_width and base_height
	members of size_hints, if they're available (X11R4 and after);
	otherwise, approximate the right thing, by using min_width and
	min_height as the base size.

	* xterm.c (x_catch_errors): Don't forget to initialize
	x_caught_error_message to the null string, so x_check_errors can
	tell when an error has occurred.