remove old closed iconv tables
/usr/lib/iconv/*.t and /usr/lib/iconv/iconv_data appear to have been used perhaps for something keyboard related in pre-history, and more recently by the old closed iconv(1).
Our iconv(1) doesn't use them, and whatever keyboard-y use they may have had (they all begin with ascii 'kbd!map') is long gone. We should remove them
(in practice, since they're closed, this means filtering them out of the closed-bins in src/Makefile and not packaging them).