Merge branch 'master' into core-updates

gnu: isync: Update to 1.2.1.

* gnu/packages/mail.scm (isync): Update to 1.2.1.

gnu: getmail: Update to 4.48.0.

* gnu/packages/mail.scm (getmail): Update to 4.48.0.

gnu: notmuch: Update to 0.21.

* gnu/packages/mail.scm (notmuch): Update to 0.21.

gnu: offlineimap: Update to 6.6.1.

* gnu/packages/mail.scm (offlineimap): Update to 6.6.1.

gnu: exim: Update to 4.86.

* gnu/packages/mail.scm (exim): Update to 4.86.

gnu: exim: Add alternate URL.

* gnu/packages/mail.scm (exim)[source]: Add alternate URL.

gnu: msmtp: Update to 1.6.3.

* gnu/packages/mail.scm (msmtp): Update to 1.6.3.
[inputs]: Add libsecret.

gnu: claws-mail: Update to 3.13.1.

* gnu/packages/mail.scm (claws-mail): Update to 3.13.1.

gnu: offlineimap: Update to 6.6.0.

* gnu/packages/mail.scm (offlineimap): Update to 6.6.0.

gnu: dovecot: Add linux-pam to inputs.

* gnu/packages/mail.scm (dovecot): Add linux-pam to inputs, enabling the
  PAM auth driver.

Merge branch 'master' into core-updates

gnu: gmime: Update to 2.6.20.

* gnu/packages/mail.scm (gmime): Update to 2.6.20.
[arguments]: Use modify-phases syntax.

gnu: dovecot: Update to 2.2.19.

* gnu/packages/mail.scm (dovecot): Update to 2.2.19.

gnu: msmtp: Update to 1.6.2.

* gnu/packages/mail.scm (msmtp): Update to 1.6.2.
  [arguments]: Use '--with-tls' configure flag instead of
  '--with-ssl' (deprecated).

gnu: esmtp: Fix 'inputs' field.

This is a followup to commit f8ae32a26a5f41466f5c7792261fdf2e78d1d35f.

* gnu/packages/mail.scm (esmtp)[inputs]: Add missing parentheses.

gnu: Add esmtp.

* gnu/packages/mail.scm (esmtp): New public variable.

gnu: Add libesmtp.

* gnu/packages/mail.scm (libesmtp): New public variable.

gnu: claws-mail: Update to 3.13.0.

* gnu/packages/mail.scm (claws-mail): Update to 3.13.0.
  [url]: Update to new location.

Merge branch 'dbus-update'