NAME
        SizeLayer -- Change the size of this nonbackdrop layer.

    SYNOPSIS
        result = SizeLayer( dummy, l, dx, dy )
        d0                  a0     a1 d0  d1

        long sizelayer( long, struct layer *, long, long);

    FUNCTION
        Change the size of this layer by (dx,dy). The lower right hand
        corner is extended to make room for the larger layer.
        If there is SuperBitMap for this layer then copy pixels into
        or out of the layer depending on whether the layer increases or
        decreases in size.  Collect damage list for those layers that may
        need to be refreshed if damage occurred.

    INPUTS
        dummy - unused
        l - pointer to a nonbackdrop layer
        dx - delta to add to current x size
        dy - delta to add to current y size

    RESULTS
        result - TRUE if operation successful
                 FALSE if failed (out of memory)

    BUGS

    SEE ALSO
        graphics/layers.h, graphics/clip.h