[DEVOPS-1120] Add compiler-specific patches to package set

Now it builds!

Author: rvl

nix/pkgs.nix

@@ -39,6 +39,9 @@ let
   # our packages
   stack-pkgs = import ./.stack-pkgs.nix;
 
+  # The compiler referenced in the stack config
+  compiler = (stack-pkgs.overlay hackage).compiler.nix-name;
+
   # Build the packageset with module support.
   # We can essentially override anything in the modules
   # section.
@@ -53,6 +56,7 @@ let
       stack-pkgs.overlay
     ];
     modules = [
+      haskell.ghcHackagePatches.${compiler}
     ];
   };