non-ASCII output for ldapsearch [PATCH]

Hello

It would be nice if ldapsearch could display non-ASCII strings in a configurable charset, instead of always encoding in base64.

I understand the current behavior is a requirement for LDIF compliance, but I believe we can add a non-LDIF compliant output, if this is what the user requested.

Attached is a quick patch that will let ldapsearch output in the charset specified by LDAP_CHARSET environment variable (inspiration from LESS_CHARSET for less(1)). That makes life much more confortable when handling non-english data.

It uses iconv() if <iconv.h> is detected. This function has been in POSIX for a while: https://pubs.opengroup.org/onlinepubs/007908775/xsh/iconv.html

Opinions? Thoughts?