reported by Rob Quinn.
add iconv external I/F (iconv.h - iconv_open()/iconv()/iconv_close()) and iconv(1) utility. TODO: - bump libc minor. - add iconv data files. - create manpages: iconv_open(3)/iconv(3)/iconv_close(3)/iconv(1)/ mkesdb(1)/mkcsmapper(1).