bug#33320: 27.0.50; `describe-key' fails to display help for C-mouse-3

[martin rudalics]

> The problems I have stem mostly from the mixing of GTK and
> X11 calls, so the goal there should be to remove the direct calls into
> X11 (especially since at some point X11 will disappear to be replaced
> by Wayland).

Maybe we could convince Glenn to set things up for us: provide gtk
equivalents of xterm.h, xterm.c, xfns.c and whatever else we would
need and the facilities for making a "pure" gtk build - one that does
not rely on xterm.h, xfns.c,...  Then people could (1) eliminate the
Lucid, Motif, non-toolkit stuff from there (2) optionally merge
gtkutil there and (3) eventually remove the X11 dependent parts.
Otherwise, this will remain a pipe dream till the end of time.

martin