Ada build status

[Richard Kenner]

I've been away for about a week, but I think I got the issues with the 
TYPE_VALUES cache resolved.  In one place, the Ada front end was changing
TYPE_UNSIGNED on a type it just made.  That was always dubious, but worked.
I changed it so it wouldn't do that anymore.

However, I get a failure running the stage2 compiler that I'll look at later
today, but it appears to be a miscompilation of *C* code (decl.c), so it's
peculiar.