iOS support

[jspahrsummers]

This will entail creating an iOS static library target, and then getting GHC to build for ARM.

[mrotondo]

As I emailed about, GHC has an issue where it can't build a stage-2 bootstrap compiler for cross-compilation (see here). Template Haskell needs a stage-2 compiler to do it's thing (see here). I used Stephen Blackheath's ghc-ios fork to try and build ObjectiveHaskell (in the iOSSupport branch), and the TH in the library prevented it from building.

Stephen is apparently working on getting cross-compilation working with TH. It definitely looks like OH uses it in some important places, so in the mean time I'm going to just use it as-is on Mac OS, so no rush on my account!

[jspahrsummers]

Yeah… I think I should get rid of uses of Template Haskell in the library itself (they're not that important), and provide the TH functions in their own module, which can be optionally imported for convenience in application code.