systemd: skip in non-systemd distros to fix world builds

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
udev: skip in systemd distros, to fix world builds

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
systemd: fix typo in FILES

Accidently managed to corrupt FILES_udev.

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
gtk-doc: parameterise the documentation directory

Not every package puts the gtk-doc infrastructure into ${S}, so allow this to be
overridden.

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
systemd: use new GTKDOC_DOCDIR and clean up

Now that gtk-doc.bbclass supports overriding the documentation directory,
systemd can just inherit gtk-doc and all of the manual operations can be
removed.

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
systemd: add missing patch headers

The reverts were by Koen and are literal revert commits, the uclibc patches were
mostly introduced by Khem.

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>