Support for --with-tm-x-support on OSes other than Linux

[Pavel Roskin <proski gnu org>]

Hello!

For some reason (most likely for no reason) the functionality of
ctrl_pressed() was limited to Linux.  In some cases (Ctrl-PgUp and
Ctrl-PgDn), ctrl_pressed() was only used on Linux console, but not in
terminal emulators for X.

I've committed a patch that enables ctrl_pressed() for all operating
systems. Just configure MC with --with-tm-x-support on QNX, OpenBSD,
whatever, and have the functionality that only Linux users could enjoy so
far!

Not all functionality is available on all terminals, but the aftificial
limitations have been removed.

Although it's possible to implement ctrl_pressed() for the GNOME edition
using Gdk events, I decided not to do so. GNOME has its own guidelines,
and very few GNOME users would expect Ctrl-PgUp to work as it did in MC.

-- 
Regards,
Pavel Roskin