Remove Integer literal constructor from RTS. It's not used anymore.
Add an operation Integer -> JSString to integer-gmp.
Remove unnecessary 'pkgroot' field from ghc-prim/packageconfig.
Add slightly hacked includes from GHC 7.6.3, in preparation for a hacked base.

This breaks base on a 64 bit host; possibly on a 32 bit one as well.
Remove .gitignore from ghc-prim and integer-gmp.

Nothing in there that isn't already in the root .gitignore.
Add slightly hacked version of base-4.6.0.1.

The changes are small enough that updating to newer base versions down the
line should be a breeze.
Add slightly hacked version of array from GHC 7.6.3.

Unboxed arrays are (and always were) completely borked. Should probably
implement a new array library from scratch using JS arrays, instead of
shoehorning C-tailored primops into JS arrays.
Update README with new build instructions.