bug#18136: 24.4.50; crash in redisplay when calling load-theme

[martin rudalics]

> IMO, FRAME_LINES for the TTY frame that is currently displayed on its
> terminal should always equal to FrameRows for that terminal (and
> similarly for FrameCols).  I thought we previously agreed on this,
> since a TTY frame usually behaves as a maximized frame.

We agreed that the total (pixel) height of the frame should not change
and the frame's windows should get resized when the menubar is turned
off and on.  But the problem is that you want that the frame's text
height should not change either and this is much more difficult to
achieve.

In principle, I have to lie about the text height, for example, in this
part of frame.c

  new_text_height = FRAME_PIXEL_TO_TEXT_HEIGHT (f, new_pixel_height);

and I'm not yet sure how to do that :-(

IIUC it amounts to changing FRAME_PIXEL_TO_TEXT_HEIGHT and
FRAME_TEXT_TO_PIXEL_HEIGHT for TTYs but I'm afraid that that is not
sufficient.  In any case, the change will be substantial.

martin