>> (/ (frame-text-height) (frame-char-height))
 >
 > 47.
 >
 >> (/ (frame-text-width) (frame-char-width))
 >
 > This is a bit random.  On 5 starts, I got 79 once, 83 once and 84 three times.
 > And the number of columns match, 79, 83 and 84.

My old patch was silly - it propagated the frame's pixel sizes instead
of the text sizes to xg_frame_set_char_size.  Please try the attached
one.  I still have two problems here: The height of the initial frame is
by six lines too small and a new frame made via C-x 5 2 is two lines
higher than the initial one.

Thanks, martin