Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
It always bothered me a bit that unit-name.[ch] contains so many
definitions that aren't really have much to do with unit nameing, for
example all the unit state definitions.
With this patch unit-name.[ch] is split into two: the file now contains
only the unit naming related operations, and everything else is split
out into a new set of files unit-def.[ch]. That's mostly unit state
stuff as well as dbus path and interface name operations.
No functional changes. This just moves code around.
(Note as both .c files include each other's headers this doesn't make
the build simpler or anything. All it does is make the C files a bit
shorter, and medicate my pretend OCD)
