bluespec: Fix build without ghc 844

ghc 8.4.4 was only required before the merge of

B-Lang-org/bsc#42

which actually is already contained in the commit we are using.

pkgs/development/compilers/bluespec/default.nix

@@ -6,24 +6,21 @@
 , fontconfig
 , gmp
 , gperf
-, haskell
 , libX11
 , libpoly
 , perl
 , pkgconfig
 , verilog
 , xorg
 , zlib
+, ghc
 }:
 
 let
   # yices wants a libgmp.a and fails otherwise
   gmpStatic = gmp.override { withStatic = true; };
 
-  # Compiling PreludeBSV fails with more recent GHC versions
-  # > imperative statement (not BVI context)
-  # https://github.com/B-Lang-org/bsc/issues/20#issuecomment-583724030
-  ghcWithPackages = haskell.packages.ghc844.ghc.withPackages (g: (with g; [old-time regex-compat syb]));
+  ghcWithPackages = ghc.withPackages (g: (with g; [old-time regex-compat syb]));
 in stdenv.mkDerivation rec {
   pname = "bluespec";
   version = "unstable-2020.02.09";
@@ -94,6 +91,5 @@ in stdenv.mkDerivation rec {
     # darwin fails at https://github.com/B-Lang-org/bsc/pull/35#issuecomment-583731562
     # aarch64 fails, as GHC fails with "ghc: could not execute: opt"
     maintainers = with stdenv.lib.maintainers; [ flokli thoughtpolice ];
-    broken = true;  # ghc-8.4.4 is gone from Nixpkgs
   };
 }