(mframe): Fix setting of frame->rfont. (mframe_get_prop): Return the average_width of a font.
(mframe): Fix setting of frame->rfont.
(mframe_get_prop): Return the average_width of a font.

xmirror/m17n-lib,xmirror/m17n-lib,xmirror/m17n-lib,xmirror/m17n-lib