ghc: 8.2.2 on armv7l doesn't build without explicit use of ld.gold.

pkgs/development/compilers/ghc/8.2.2.nix

@@ -58,6 +58,8 @@ stdenv.mkDerivation (rec {
     "--with-gmp-includes=${gmp.dev}/include" "--with-gmp-libraries=${gmp.out}/lib"
   ] ++ stdenv.lib.optional stdenv.isDarwin [
     "--with-iconv-includes=${libiconv}/include" "--with-iconv-libraries=${libiconv}/lib"
+  ] ++ stdenv.lib.optional stdenv.isArm [
+    "LD=${stdenv.cc}/bin/ld.gold"
   ];
 
   # required, because otherwise all symbols from HSffi.o are stripped, and