Xconq now C++ compatible

[Jim Kingdon]

> I have just checked in Ed's C++ compatibility patches. This means that the
> x11, tcltk, sdl and curses interfaces now will build also with a C++
> compiler.

Cool!

I was hoping these would get checked into CVS rather than sitting
around in someone's private branch.

Congrats to the chefs.  I've been doing a little K&R->C89 stuff here
and there, but nothing on nearly this scale.