[cplus] An initial use of the canonicalizer

[Michael Elizabeth Chastain]

drow> It can't be fixed.  I spent a miserable long time last year trying.
drow> There's not enough information to figure out whether the constructor is
drow> explicit or implicit.

Oh, well.  What can't be cured must be endured.

On the bright side, dwarf-1 is almost completely gone from
gcc HEAD (there are just remnants in old 'if' statements).
Maybe stabs+ will go away by 2010.

Michael C