nmcli has documentation strings embedded. Those strings are extracted
from gtk-doc comments, using pygobject and put in the generated file
"clients/common/settings-docs.c".
This file "clients/common/settings-docs.c" is disted, so from
a source tarball you can build nmcli without enabling introspection.
However, when building from a git-tree, the file is missing and
thus one cannot build --with-nmcli unless also using at least
--enable-introspection to generate "clients/common/settings-docs.c".
That is inconvenient. Especially during cross-compilation, where
one also needs python and pygobject in the foreign architecture (because
the generation of "settings-docs.c" loads the built libnm.so via
pygobject). It is bad because nmcli is an essential part of
NetworkManager, so building --without-nmcli is not a great option.
Previously, the only alternative was to pre-generate a source tarball
on a separate machine and build that. This however complicates efforts
to automatically build git snapshots of NetworkManager.
Fix that by commiting "clients/common/settings-docs.c.in" to git.
When building with --disable-introspection, the pre-generated
file is used instead. This is fine, because the file only depends
on static, checked-in documentation strings that seldomly change.
Also add a check target to notice when the pre-generated file differs
from what we are about to generate during --enable-introspection.
That happens when editing one of the gtk-doc entires. In this case,
`make check` will notify that the pre-generated "settings-docs.c.in"
file needs updating too.
Yes, when changing gtk-doc comments you need to updte the file manually.
At least, the check failure notifies you.
