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.
Many people prefer to avoid clearing /tmp and /var/tmp, and
distributions often have explicit settings for how often to clear them
if at all. Overriding those with systemd currently requires overriding
all of /usr/lib/tmpfiles.d/systemd.conf via
/etc/tmpfiles.d/systemd.conf, copying across all the other entries, and
updating that override when systemd.conf changes.
Move the /tmp and /var/tmp entries from systemd.conf to a separate
tmp.conf, making them easier to override without affecting the rest of
systemd.conf.
