Heirloom mailx

This release adds an option to discard empty messages. It adds support for SMTP AUTH PLAIN. Messages with illegal byte sequences in non-interactive mode are not rejected anymore but sent as "application/octet-stream" instead. Attachments with such sequences are always sent in this way. Automatic outgoing character set selection now works for each part of a multi-part message separately.

Fixes were made to the handling of multibyte
characters in base64-encoded message parts. Some
minor issues were also fixed.

MIME message parts that are not of type "text/" are now always encoded in base64 to avoid issues with CRNL conversion. Character set conversion is now applied to attachments if they have the "text/" content type. An interoperability problem concerning maildir folders has been fixed. An invalid memory access when determining the current message in threaded mode has been fixed. It is now possible to build with more recent versions of Mozilla NSS.

This release fixes bugs in the base64 encoder, in generated S/MIME headers, regarding messages in character sets with state-dependent encodings, and in the handling of the "prompt" variable.

The program has been integrated into the Heirloom project as "mailx". An
error in SMTP address syntax that caused mailx to fail sending messages
to a Sendmail X server has been fixed. The SMTP AUTH password can now be
typed directly at the terminal. A SMTP transfer child process can now be
aborted in a controlled manner with SIGTERM, saving the current message
to the dead.letter file.