hheretic: add missing libGL and libGLU depends

Without the change the build fails as https://hydra.nixos.org/build/294989234:

checking for OpenGL support... no
configure: error: *** OpenGL not found!

ZHF: #403336

pkgs/by-name/hh/hheretic/package.nix

···
   fetchFromGitHub,
   SDL,
   SDL_mixer,
+  libGL,
+  libGLU,
   autoreconfHook,
   gitUpdater,
 }:
···
   buildInputs = [
     SDL
     SDL_mixer
+    libGL
+    libGLU
   ];
 
   strictDeps = true;