We finally got the OK from all contributors with non-trivial commits to
relicense systemd from GPL2+ to LGPL2.1+.
Some udev bits continue to be GPL2+ for now, but we are looking into
relicensing them too, to allow free copy/paste of all code within
systemd.
The bits that used to be MIT continue to be MIT.
The big benefit of the relicensing is that closed source code may now
link against libsystemd-login.so and friends.
It is customary that pam modules do not log debugging information by default.
Usually they offer a 'debug' option.
Add a boolean debug= option to pam_systemd.so.
This will solve bug
https://bugzilla.redhat.com/show_bug.cgi?id=705427
Commit 53d5582fa0 was not sufficient to fix it,
because in Fedora rsyslog is configured to write even LOG_DEBUG messages to
/var/log/secure by default.
