gtk3: use require_active_variants like gtk2 does

[ryandesign (Ryan Carsten Schmidt)]

I fixed gtk2 to use require_active_variants. Then I wanted to make gtk3 do the same. Then I realized gtk3 was already using require_active_variants but slightly differently.

This patch updates gtk3 to do it the way gtk2 now does.

There is a slight change in behavior: previously, gtk3+quartz could not be installed if pango+quartz+x11 was installed; it required pango+quartz (without +x11). Was this restriction necessary? If not, we should remove it, as in the attached patch. If the restriction really was necessary, I'm guessing we should add it to gtk2 as well.

There was no corresponding restriction for +x11. The port already allowed gtk3+x11 to be installed if pango+quartz+x11 was installed, and this patch doesn't change that.

[ryandesign (Ryan Carsten Schmidt)]

proposed patch

[neverpanic (Clemens Lang)]

Thanks, I just wasn't aware pango's +x11 and +quartz don't conflict.

r103160.

[ryandesign (Ryan Carsten Schmidt)]

I forgot that for awhile too :P