GTK+ 2 specific code inside wx terminal

[Mojca M. <moj...@gm...>]

Hi,

I would like to ask for a bit of help with fixing some opportunistical
linking against GTK+ when wxWidgets is used:
    https://trac.macports.org/ticket/50199

The problem is that as soon as pkg-config finds GTK+ version 2 on the
system and if wxWidgets terminal is enabled, gnuplot links against
GTK2 even if no GTK code is being used at all. And if wxWidgets uses
GTK 3, compilation fails because gnuplot tries to call some functions
that no longer exist in GTK 3.

(I can move the ticket to the gnuplot tracker, but I maybe some
autoconf or GTK guru could help a bit.)

Mojca