haskell-gi, gi-gdkx11: fix builds

The `haskell-gi` build fails its doctests because of a missing
library; I'm not 100% convinced that setting it to `dontCheck` is the
right thing to do, but I don't have a better idea at the moment.

The `gi-gdkx11` build fails because, surprise, Gdk-X11 isn't found; by
looking around in my store, I found that that that library seems to
live in gtk3 these days; this override is just a stop-gap, though,
I've also submitted the change to cabal2nix that I believe will fix
the automatic generation of the package in the future.

pkgs/development/haskell-modules/configuration-common.nix

@@ -422,6 +422,9 @@ self: super: {
   # https://github.com/evanrinehart/mikmod/issues/1
   mikmod = addExtraLibrary super.mikmod pkgs.libmikmod;
 
+  haskell-gi = dontCheck super.haskell-gi;
+  gi-gdkx11 = super.gi-gdkx11.override { gdk-x11 = pkgs.gtk3; };
+
   # https://github.com/basvandijk/threads/issues/10
   threads = dontCheck super.threads;