* Use emscripten branch of GHCJS for 8.6
* Adds release-linux-only.nix (for hydra with no mac builders)
* Sets HOME to a temp dir once per derivation to help performance of emcc
* Updates materialization
* Uses symlinks to reduce ghc derivation size for wrapped ghcjs
* Removes compiler-nix-name test
This test checked that the default compiler was overridden by the
compiler-nix-name arg. There is no default any more.
The GHCJS branches used include fixes for:
* hs$ret_1 typo (should be hs$ret1)
* A bignum issue