x11-servers/xorg-vfbserver depends on x11/xkeyboard-config

[Robert Simmons]

When I start Xvfb it fails with the following error:
XKB: Failed to compile keymap

It appears that xvfb now requires xkeyboard-config. After installing
x11/xkeyboard-config everything works as expected.

I wanted to modify the port to add this dependency, but I wanted to
make sure it is correct. I looked in the /usr/ports/Mk/bsd.xorg.mk and
did not see this port listed to add it to the USE_XORG= line in the
Makefile. In this case, should this be set in RUN_DEPENDS= ?