bug#7296: display-pixel-height not enough

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 02 Nov 2010 14:25:49 +0100
> From: "Jan D." <jan.h.d@swipnet.se>
> Cc: 
> 
> >> They are already implemented for X
> > Where?  Maybe I misunderstood, but my impression from this discussion
> > was that they aren't and actually the need for them and their utility
> > are debatable.
> >
> 
> In xterm.c, do_ewmh_fullscreen.  I don't know why you say they are 
> debatable

Like I said, I probably misunderstood.  It's easy, what with all the
bikeshedding in this thread.

> it is the only way to correctly make an Emacs frame full 
> height or full width or fullscreen or maximized.  It lets the WM do the 
> job, so Emacs doesn't need to count pixels and panels and taskbars and 
> autohide and whatever.

I think the only practical way of doing the same on Windows is to
exclude the area reserved for the task bar.  It could be that in a few
rare cases this will produce less pixels than are strictly possible.
So what are the objections to this (my original suggestion) at this
point?  To be 100% clear, I suggest:

  . on w32, return the dimensions sans the reserved part(s)
  . on other GUI platforms, no change from the current behavior