- Prevent from auto-detecting fam library when FAM option is unset
- Add IDN option and stop auto-detection of libidn
- Prefer base iconv
- Add USE_PERL5=build since it is needed only for build
- Use ${opt}_CONFIGURE_OFF knob for MAILWRAPPER option.
PR: ports/188839
Submitted by: Yasuhiro KIMURA <yasu@utahime.org>