* iconv/gconv_conf.c (add_module): Complete rewrite. Use cleverer
data structures and avoid creating intermediate representations
first. Rewrite also all helper functions.
* iconv/gconv_db.c (find_derivation): Use new data structure for
module database.
* iconv/Versions: Remove __gconv_nmodules.
* iconv/iconv_prog.c: Rewrite generation of charset name list to
use new data structure.
* iconv/gconv_int.h (struct gconv_module): Add new elements for
database data structure.
(__gconv_modules_db): Update type.
(__gconv_transform_dummy): Removed.
* iconv/gconv_builtin.h: Remove dummy transformation.
* iconv/gconv_simple.c: Remove __gconv_transform_dummy.