(stringify, raw_before, raw_after): Use this type instead of char.
(collect_expansion, dump_single_macro): Keep track of white space
after # and around ## tokens, since the C Standard requires a
diagnostic if the white space doesn't match during a redefinition.
(sharp_token, sharp_sharp_token): Labels renamed from hash_token and
hash_hash_token for naming consistency.

From-SVN: r9036