system_x11 variant ignored during upgrade

[Jonathan Stickel]

I am attempting to upgrade my outdated ports, and am curious to see how 
the newly implemented "system_x11" variant will work.  I upgraded with:

$ sudo port -u upgrade outdated

and sure enough, one of my outdated ports depends on xorg-libX11. 
However, the system_x11 variant was ignored, even though I have it set 
in /opt/local/etc/macports/variants.conf.  If I install xorg-libX11 
directly by

$ sudo port install xorg-X11

then it seems to work.  Is this a bug that I should report on the tracker?

Thanks,
Jonathan