XFree86 support for GDB

This patch adds XFree86 module support to GDB 6.0 and CVS snapshot as of 2003-09-16.

I have found the original patch for GDB 4.18 somewhere on the internet.

Tested for i386 and AMD64 architectures with XFree86 v4.x.x on SuSE Linux.

Patch against GDB 6.0: gdb-xfreemod-6.0.diff (Colorized)
Patch against CVS (as of 2003-09-16): gdb-xfreemod-head-20030916.diff (Colorized)
Older versions: For CVS as of 2002-11-07