V3 PATCH: Fix const-correctness in use of iconv

[Gabriel Dos_Reis]

Phil Edwards <pedwards@disaster.jaj.com> writes:

| Here's the patch.  Note that all the const qualifiers on the types have to
| be removed again -- I think this makes the seventh flip-flop for __cfrom,
| can we set a record? -- for this adaptor to work.
| 
| This builds under Solaris 8, which was one of the platforms which previously
| failed without const.  I don't have a glibc 2.2 box yet; that still needs
| to be tested to examine the other case.
| 
| Somebody else will have to tweak up the comment, write a ChangeLog,
| and check in the code; apparently there is a tornado approaching, so I
| probably won't have time.

Phil, thanks for taking this.

Currently, I don't have the time, unfortunatley, to polish your patch
-- we definitely need a codecvt.tcc.  That is for the next week unless 
Bnejamin beats me...

-- Gaby