haskell.packages.ghc944.X11-xft: add missing build-time dependencies

[peti]

The packages has additional system dependencies when compiled in the ghc-9.4.x package set.

[sternenseemann]

As pointed out in #214145 (comment), this packages does not genuinely have more dependencies, but Cabal is overeager in checking PKG_CONFIG_PATH. I would prefer a different way of fixing this, sadly upstream Cabal hasn't come up with a solution yet.

[peti]

I am all for implementing a better solution once we know one. Until then, I believe that simply adding the missing dependencies to fix the build is kinda okay. Those are build-time dependencies only and the override we added does not cause any long-term maintenance costs. Also, the ghc-9.4.4 package set is hardly used by anyone at the moment and fixing builds there in an inperfect way is not going to cause trouble to anyone but, like, expert Haskell uses who choose to live on the bleeding edge.

[sternenseemann]

I'm mostly worried about maintainability here, a better solution is probably doing it like this: #214446

I really hope Cabal 3.10 will include a fix for this that we can somehow backport to 3.8 and 3.9…