Extension to the FFI to allow macro expansions to be avoided

[Sven Panne]

Fergus Henderson wrote:
> I'd rather fix GHC so that interfacing with C macros works with ghc -fasm.
> The equivalent works fine with the Mercury implementation ("mmc --target asm"
> generates assembler for the Mercury code and C stubs for the FFI glue),
> so it's clearly possible.

How does Mercury handle something like the "broken" macros we discussed recently
in its different back-ends?

Cheers,
    S.