libx11: Disable generating PS/PDF for the spec

libx11: Disable generating PS/PDF for the spec

libx11 would search for groff and ps2pdf to generate a PS/PDF of
the specs, if a broken ps2pdf (fedora 14 testing) is installed the
build will fail barfing about Fontmap.local. The PS/PDF does not
appear to be in any FILES_* so we can disable the PS/PDF generation
at tall and not run into the issue.

The fedora bug is at: https://bugzilla.redhat.com/show_bug.cgi?id=610301.

libx11.inc: Disable groff, ps2pdf effectively disabling generating
a PS/PDF for the X11 spec
xorg-lib-common.inc: Bump the INC_PR used by libx11.inc. This sadly
affects quite some other recipes too.