iconv API enhancements. (fwd)

[Sam Varshavchik]

I looked at the iconv API to replace charset mapping functionality in my 
application.  Right now I maintain my own tables for about a dozen 
charsets.  Going to iconv, gaining awareness of a few hundred charsets, and 
reducing the memory footpring by .5MB looks very attractive.  However, I 
couldn't do that due to some missing API functionality which, I think, 
would be very useful for applications to have.

* An API to enumerate available charsets.  I could, of course, open and 
parse gconv-modules myself.  But glibc already does that anyway, so why 
reinvent the wheel?

* Various character set properties.  Specifically, I'd like to know if a 
charset is a composite charset, like iso-2022-jp or shift_jis, which uses 
shift sequences to jump between different component charsets.  That means I 
cannot search for a text string in that character set, natively, and I must 
convert everything to some other charset, like utf-8.