Update mail/mutt to mutt 1.9.5 
- GPGME S/MIME non-detached signature handling.
- A compilation issue with ncurses-6.1 when tinfow is split out. Hopefully the fix doesn't impact anyone: please let me know of any issues.
- Regular expression crashes and weird behavior problems on MacOS (and possibly other BSDs). This was most noticeable with the recent Xcode 9.3 release, but the issue has existed for a while.
- GSSAPI authentication issues, which may have affected Exchange users. We've changed behavior to match the RFC. If you are negatively impacted by this, please let me know.