man rules were repeating the same information in too many places,
which was error prone. Those rules can be easily generated from .xml
files. For efficiency and because python is not a required dependency,
Makefile-man.am is only regenerated when requested with

  make update-man-list

If no metadata in man/*.xml changed, this file should not change. So
only when a new man page or a new alias is added, this file should
show up in 'git diff'. The change should then be committed.

If the support for building from git without python was dropped, we
could drop Makefile-man.am from version control. This would also
increase the partial build time (since more stuff would be rebuild
whenever sources in man/*.xml would be modified), so it would probably
wouldn't be worth it.

There shouldn't be any functional change. This is an 'automake include',
so the generated Makefile is the same (apart from ordering).

Previously, errors would be ignored. Now they are not. But I don't see
how we could fail to create the directory, so I don't think that it
matters.

When running without a user session, tests fail.

The test was originally added with this commit message:
"ask-password: supported plymouth cached passwords"

Clearer, and spares the temp variable.

False positives pop up otherwise.

FAIL: test-unit-name (exit: 134)
================================

Failed to open /dev/tty0: Permission denied
Failed to create root cgroup hierarchy: Permission denied
Assertion 'manager_new(SYSTEMD_SYSTEM, &m) == 0' failed at src/test/test-unit-name.c:125, function test_unit_printf(). Aborting.

adds test of:
strv_find
strv_find_prefix
strv_overlap
strv_sort
streq_ptr
first_word

Splits tests of util.c into own file to avoid clutter as we add more.

Removed a few prints and uses _cleanup_free_ to make the tests more focused.

As of 3cdebc21 support for
distro specific boot up runlevels has been dropped.

Mukund Sivaraman pointed out that cryptsetup(5) mentions the "read-only"
option, while the code understands "readonly".

We could just fix the manpage, but for consistency in naming of
multi-word options it would be prettier to have "read-only". So let's
accept both spellings.

BZ: https://bugzilla.redhat.com/show_bug.cgi?id=903463

test-strv.c: Leaves main clean for additional tests

Fixup for 350b6a65.

Sometimes it is useful to look at them, and they don't take
up any significant amount of space. Keeping them also avoids
the message about files being removed at the end of make
run.

- fix typo
- use compiled systemd-nspawn
- drop --capability=... from systemd-nspawn invocation, is is the default now
- simplify sudo make invocations

This allows one templated unit to refer to another templated unit
at installation time.

Examples:

> grep WantedBy ~/.config/systemd/user/mpop@.timer
WantedBy=services@%i.target

> srv disable mpop@iit.timer
rm '/home/alxchk/.config/systemd/user/services@iit.target.wants/mpop@iit.timer'
> srv enable mpop@iit.timer
ln -s '/home/alxchk/.config/systemd/user/mpop@.timer' '/home/alxchk/.config/systemd/user/services@iit.target.wants/mpop@iit.timer'
Based-on-patch-by: Oleksii Shevchuk <alxchk@gmail.com>

When the username was not explicitly specified, both %U and %u would
print the username. Make %U always print UID.

No functional change. This makes it possible to use them in install.c.