Log Message:
Update to 1.8.19. From the changelog:
- Fixed a security problem in msmtpd: mail addresses starting with '-'
  could be interpreted as options of the pipe command.
- msmtpd now supports logging to syslog or to a file with the
  option --log, and authentication (for special use cases) with the
  option --auth.
- The 'from' command now accepts patterns (as in shell file name
  matching) so that many envelope from addresses given with --from can
  match the same account
- Added support for %H, %C, %M in the domain command
- msmtpd now supports sysexits.h error codes from the pipe command