Second change to get kdebase3 to work on amd64. kdebase builds a plugin
called kxkb.so, which links against libxkbfile. This is fatal on
amd64 because XFree86 does not normally provide libxkbfile.so, and it is
a guaranteed fatal error to link non-PIC code into a .so file.
I have only arranged for libxkbfile.so to be build on amd64 so as to
not risking distrubing dependencies on other platforms.