GHC LLVM Mangler
This script processes the assembly produced by LLVM, rearranging the code
so that an info table appears before its corresponding function. We also
use it to fix up the stack alignment, which needs to be 16 byte aligned
but always ends up off by 4 bytes because GHC sets it to the
starting value in the RTS.
We only need this for Mac OS X, other targets don't use it.