systemd: use pager for --test and --help
Add quotes to warning message

The message for SYSTEMD_LOG_LEVEL= looked a bit strange.
test-engine: fix access to unit load path

Also add a bit of debugging output to help diagnose problems,
add missing units, and simplify cppflags.

Move test-engine to normal tests from manual tests, it should now
work without destroying the system.
systemd: return the first error from manager_startup()
test-cgroup-mask: pass on kernels without memory controller

It seems that unit_get_siblings_mask returns the controllers
filtered by what is available, but get_members_mask and
get_cgroup_mask do not. This just fixes the test following the
symptoms.
test-cgroup-mask: fix masks in test and enable by default

Commit 637f421e5c6a ("cgroups: always propagate controller membership
to siblings") changed the mask propagation logic, but the test wasn't
updated.

Move to normal tests from manual tests, it should not touch the system
anymore.
path-lookup: make SYSTEMD_UNIT_PATH more flexible

It can now contain more than one directory, and can be used
to only prepend, not totally override, the normal load path.
systemd-verify: a simple tool for offline unit verification

This tool will warn about misspelt directives, unknown sections, and
non-executable commands. It will also catch the common mistake of
using Accept=yes with a non-template unit and vice versa.

https://bugs.freedesktop.org/show_bug.cgi?id=56607
systemd-verify: check man pages
man: add systemd-verify(1)