Update default Haskell compiler from GHC 7.8.3 to 7.8.4.

pkgs/development/compilers/ghc/7.8.3.nix

@@ -1,44 +0,0 @@
-{ stdenv, fetchurl, ghc, perl, gmp, ncurses }:
-
-stdenv.mkDerivation rec {
-  version = "7.8.3";
-  name = "ghc-${version}";
-
-  src = fetchurl {
-    url = "http://www.haskell.org/ghc/dist/7.8.3/${name}-src.tar.xz";
-    sha256 = "0n5rhwl83yv8qm0zrbaxnyrf8x1i3b6si927518mwfxs96jrdkdh";
-  };
-
-  buildInputs = [ ghc perl gmp ncurses ];
-
-  enableParallelBuilding = true;
-
-  buildMK = ''
-    libraries/integer-gmp_CONFIGURE_OPTS += --configure-option=--with-gmp-libraries="${gmp}/lib"
-    libraries/integer-gmp_CONFIGURE_OPTS += --configure-option=--with-gmp-includes="${gmp}/include"
-    DYNAMIC_BY_DEFAULT = NO
-  '';
-
-  preConfigure = ''
-    echo "${buildMK}" > mk/build.mk
-    sed -i -e 's|-isysroot /Developer/SDKs/MacOSX10.5.sdk||' configure
-  '' + stdenv.lib.optionalString (!stdenv.isDarwin) ''
-    export NIX_LDFLAGS="$NIX_LDFLAGS -rpath $out/lib/ghc-${version}"
-  '';
-
-  # required, because otherwise all symbols from HSffi.o are stripped, and
-  # that in turn causes GHCi to abort
-  stripDebugFlags = [ "-S" "--keep-file-symbols" ];
-
-  meta = with stdenv.lib; {
-    homepage = "http://haskell.org/ghc";
-    description = "The Glasgow Haskell Compiler";
-    maintainers = [ maintainers.marcweber maintainers.andres maintainers.simons ];
-    inherit (ghc.meta) license;
-    # Filter old "i686-darwin" platform which is unsupported these days.
-    platforms = filter (x: elem x platforms.all) ghc.meta.platforms;
-    # Disable Darwin builds: <https://github.com/NixOS/nixpkgs/issues/2689>.
-    hydraPlatforms = filter (x: !elem x platforms.darwin) meta.platforms;
-  };
-
-}