alias branch

[Simon Taylor]

Hi,

This is mainly to David Overton.

I've updated the alias branch. The problem is that compiler/rl_code.m
contains several switches with 340 elements, which results in
long compile times (>30 minutes), so committing this as is really
isn't a good idea (although it is a good test case).

One thing I was considering doing was to reincarnate the mercury_compile.pp
file to allow the Aditi support to be conditionally left out of the compiler.
Any other suggestions?

Simon.