new codegen patches

[John Dias]

As you may have noticed, I have finally pushed a large number of patches 
for the new code generator. The new codegen is still off by default, so 
for the most part, this patch should not have any effect on compiled 
programs. I validated the patches, but please let me know if there are any 
problems.

In case you're wondering about the status of the new code generator: There 
are still bugs that show up with the stage2 build, although the regression 
testsuite and nofib testsuite work with the stage1 build. Hopefully, I'll 
have some more patches soon.

Thanks,
John