This allows us to deprecate GHCJS 8.4 (which makes sense, as vanilla GHC
< 8.6 is already deprecated).
We re-use GHCJS from reflex-platform, which unfortunately isn't
up-to-date with latest GHC and is only 8.6. The benefit of using
reflex-platform is that it provides nix expressions for GHCJS + a binary
nix cache.
reflex-platform patches text to use a JS-String based internal
representation for performance reasons, so we provide a few haskell
dependencies from reflex-platform as well:
- hashable
- attoparsec
As those rely on text's internal representation but have been patched
for reflex-platform.
