window_update_background_c

	window_update_background_c(type.i4.v)

	This routine updates the background image text in memory from
	the current screen text.  This routine should be called after
	non window manager routines (TVx) have been called to update
	the screen.

	type		type of handling for occluded regions
			(WMNGR_DONT_CHANGE -> leave the current memory image
					      of the cell unchanged,
			 WMNGR_CLEAR_IT -> fill the cell with a blank)

	Related functions:

	window_init, window_intype, window_construct(_c), window_create(_c),
	intro_tv_windows

	C/C++ usage:

	int	type = WMNGR_DONT_CHANGE;

	window_update_background_c(type);