initial version of iconv support checked in

[Jeff Johnston]

This is just to note that the initial version of Artem Bityuckiy's iconv 
code has been checked in.  It can be activated using the configuration 
option:

  --enable-newlib-iconv

Builtin iconv converters can be selected using the configuration option:

  --enable-newlib-builtin-converters

This iconv code cannot currently be used with i686-pc-linux-gnu which 
has its own iconv support.

Thanks to Artem for this major piece of work.

-- Jeff J.