We need this for a little little longer :(

This reverts commit 1de8383a.

This removes libnm-glib, libnm-glib-vpn, and libnm-util for good.
The it has been replaced with libnm since NetworkManager 1.0, disabled
by default since 1.12 and no up-to-date distributions ship it for years
now.

Removing the libraries allows us to:

* Remove the horrible hacks that were in place to deal with accidental use
  of both the new and old library in a single process.
* Relief the translators of maintenance burden of similar yet different
  strings.
* Get rid of known bad code without chances of ever getting fixed
  (libnm-glib/nm-object.c and libnm-glib/nm-object-cache.c)
* Generally lower the footprint of the releases and our workspace

If there are some really really legacy users; they can just build
libnm-glib and friends from the NetworkManager-1.16 distribution. The
D-Bus API is stable and old libnm-glib will keep working forever.

https://github.com/NetworkManager/NetworkManager/pull/308

Although some paths related to DBus and PolicyKit are present in
their pkg-config files, those paths might not be writable for the
user. To solve this issue, some build options are present that can
be used to choose a different location.

However, usually these paths are relative to some other variables
such as `prefix`, `datadir`, etc. Using the `define_variable`
option the relative path can be change to point to a directory
under prefix.

These paths are now using relative paths based on the installation
`prefix` and their related options have been removed as they are
unnecessary now. Only `dbus_conf_dir` option has been left because
it must be modified depending on the distribution[0].

[0] contrib/fedora/rpm/NetworkManager.spec

meson is able to get variables defined in pkg-config files such as
directory paths. PolicyKit defines in its pkg-config file the path to
the directory where `policy` files are present.

This removes the `polkit_dir` option to ease the move to start using
those variables. The `polkit` variable has also been converted to
boolean.

Fedora spec script has also been updated accordingly.

Move the autotools check on settings docs to a shell script and call
it from meson too.

Also affects documentation and translated strings.
Reported-by: Flavio Leitner <fbl@redhat.com>

Turn the vapi option into a combo that allows autodetection and check
whether all prerequisites are satisfied (including introspection
support) when vapi is explicitly enabled.

#28

Add a configure option to disable eBPF support in n-acd.

Note that, even if eBPF is not supported, n-acd requires a kernel >
3.19, which means that the setsockopt(..., SO_ATTACH_BPF) option must
be defined. To allow building on older kernels without modifying the
n-acd code, we inject the SO_ATTACH_BPF value as a preprocessor define
in the compiler the command line.

a40949267 build: add CI run without ebpf
044db2056 n-acd: drop redundant headers
6a391cd83 n-acd: fix build without eBPF
bb194cf09 n-acd/config: make transport mandatory
ec2865743 build: drop unused c-sundry
721d9d84f n-acd: inline c_container_of()
1a7ee317c util/timer: fix coding-style
6c96f926b util/timer: fall back to CLOCK_MONOTONIC if necessary
4ea3165fc n-acd: only use CLOCK_BOOTTIME if really necessary
c1b853c6c util/timer: cleanup headers
b1d6ad272 n-acd: add destructors that return void
185be55b6 test-bpf: skip test in case of unsufficient privs
84a40e8fa build: add NEWS file
bf11443ff build: mention mailinglist in readme
e2797984a test-bpf: drop bpf-filter.h
668ed3c82 subprojects: pull in updates
dd8cab3f0 test-veth: reduce parallel execution to 9
68b09ba2b build: update AUTHORS
3f77e3e88 test: make function headers valid C
5275a5120 test: get rid of spurious tab
037df412c n-acd: make struct initializers valid C
346ec0c67 build: upgrade CI
38682a36d n-acd: fix signed vs unsigned comparison
5e7578b33 bpf: properly zero out trailing bpf_attr space
ee1e432ae probe: fix coding-style
a143540f9 build: use lower-case build options
835533e7d build: minor style fixes
2bd6d1d29 build: get rid of tabs
b14979934 eBPF: make compile-time optional
6f13c27ee n-acd: filter out invalid packets
4e6a169a0 build: sync with c-util repositories
6c4a9117b build: document eBPF kernel requirement
3ef08394d n-acd: don't remember dropped defense attempts
4dff8771f n-acd: fix coding-style
b11fb9706 n-acd/config: default to the RFC-specified timeout
d885bb3b7 n-acd/event: don't expose the type of operation that caused a conflict
e2f87e047 TODO: drop remaining items
f06993856 test/veth: reduce the number of probed addresses
8b4f7ed64 test/veth: bump the timeout a bit
14e4606f6 n-acd/probe: don't cap the jitter at 4s
a0247b86f test/veth: fix stackvariable corruption
a64ac8389 n-acd/probe: update comments
aa9c25bc1 n-acd/handle_timeout: update comments
b6c2df3a9 timer: rename timer_pop() to timer_pop_timeout()
47c657a8d test: fix handling of child addresses
27168ba9e timer: move timer_read() from n-acd.c to util/timer.c
21a1e37aa timer: require timer to be explicitly rearmed
ee1080820 bpf/map: make key/value sizes self-documenting
fd444353e test/veth: rework test
ba2bc433c test: rework child_ip() helper
07881b8da test: silence a warning
38da00b0a test/bpf: make tests for map modifications more comprehensive
6a2ffd23a test/timerfd: for documentation purposes verify the kernel API
01a9cf54b probe: move from ms to ns internally
4fe438dd9 n-acd: move to use the Timer utility library
e098cfc79 util: add a timer utility helper
8ea196e5b subprojects: pull in c-sundry
0c0b3c29f acd/probe: do not subscribe to packets in FAILED state
9c922ea3d acd/probe: introduce probe_{un,}link() helpers
024a830e6 acd/probe: use unschedule() helper in free()
b098a3bcc tests/veth: minor fixes to the test
fe3d9578a acd/packet: consider unexpected packets a fatal error
34d7656d7 acd: stop state-machine after USED or CONFLICT events
7d9e5ec6b acd: don't declare iovec entries inline
7afd8d8a3 tests: add veth test
26a737b42 tests/veth: add helper for adding IP addresses to child device
e73a37a11 probe: store a userdata pointer in the probe object
327e82625 test: introduce loopback helper
0682b15f8 acd: reduce default map size
afead881f tests: reinstate loopback test
4527d2f71 BPF: move and document the eBPF helpers
88bacc022 socket filter: move to the new eBPF helpers
245104d5c tests: skip tests if lacking permissions
195d9ff5a n-acd: rework API to support many probes on a context
ab440eb99 eBPF: never return packets that userspace should unconditionally drop
ac933f412 eBPF: add eBPF helper functions

git-subtree-dir: shared/n-acd
git-subtree-split: a40949267923c45cb232fa4c1d60eafacee4b36e

Handle all rc managers paths through the same code.

(cherry picked from commit 2fd75598)

Handle all dhcp client paths through the same code.

(cherry picked from commit 36b0e461)

dhcpcd version 6, the first supporting IPv6, was released more than 5
years ago. Remove all checks on version number and IPv6 support.

(cherry picked from commit e0c49d73)

dhclient 4.0 was released more than 10 years ago. I think it is
reasonable to expect that nobody is using an older version today.

https://source.isc.org/cgi-bin/gitweb.cgi?p=dhcp.git;a=shortlog;h=refs/tags/v4_0_0
(cherry picked from commit 9e61ea70)

Allow specifying a non-existent path.

(cherry picked from commit 794e499a)

Handle the iptables, dnsmasq and dnssec-trigger paths in the same way
through common code.

The path set by user must be accepted as is, even if does not exist,
because this is a requirement for cross-compilation. When user does
not specify a path, search a predefined set of paths and fall back to
an hardcoded one.

(cherry picked from commit 220dea09)

Handle all rc managers paths through the same code.

Handle all dhcp client paths through the same code.

dhcpcd version 6, the first supporting IPv6, was released more than 5
years ago. Remove all checks on version number and IPv6 support.

dhclient 4.0 was released more than 10 years ago. I think it is
reasonable to expect that nobody is using an older version today.

https://source.isc.org/cgi-bin/gitweb.cgi?p=dhcp.git;a=shortlog;h=refs/tags/v4_0_0

Allow specifying a non-existent path.

Handle the iptables, dnsmasq and dnssec-trigger paths in the same way
through common code.

The path set by user must be accepted as is, even if does not exist,
because this is a requirement for cross-compilation. When user does
not specify a path, search a predefined set of paths and fall back to
an hardcoded one.

suspend-resume must be selectable, out of for possible options.
We can do auto-detection based on present libraries, but it
shall be selectable. Like it is with autotools.

- always define the SESSION_TRACKING_* defines to replace
  "#ifdef" with "#if".

- drop defining the consolekit database path CKDB_PATH in
  config.h. The path was not customizable via configure/meson.

- fix meson build to enable consolekit support for session tracking
  without also enabling logind/elogind session tracking.
  logind/elogind is mutually exclusive, but consolekit session tracking
  goes together just fine.

"debug" was documentation in `man NetworkManager.conf` as a valid
logging backend. However, it was completely ignored by
nm_logging_syslog_openlog().
In fact, it makes not sense. Passing debug = TRUE to
nm_logging_syslog_openlog(), means that all messages will be
printed to stderr in addition to syslog/journal. However, when
NetworkManager is daemonizing, stderr is closed.
Whether NetworkManager is daemonizing depends entirely on command
line options --no-daemon and --debug. Hence, the logging backend "debug"
from the configuration file either conflicts or is redundant.

Also, adjust logging backend description in `man NetworkManager.conf`.

Also, log a warning about invalid/unsupported logging backend.

(cherry picked from commit 2ccf6168)

"debug" was documentation in `man NetworkManager.conf` as a valid
logging backend. However, it was completely ignored by
nm_logging_syslog_openlog().
In fact, it makes not sense. Passing debug = TRUE to
nm_logging_syslog_openlog(), means that all messages will be
printed to stderr in addition to syslog/journal. However, when
NetworkManager is daemonizing, stderr is closed.
Whether NetworkManager is daemonizing depends entirely on command
line options --no-daemon and --debug. Hence, the logging backend "debug"
from the configuration file either conflicts or is redundant.

Also, adjust logging backend description in `man NetworkManager.conf`.

Also, log a warning about invalid/unsupported logging backend.

It's deprecated and has been replaced by libnm for 6 major releases now.

Its use in modern distributions has faded to the point it can probably
be safely removed.

The `settings-docs.c` file is generated by processing the
`nm-property-docs.xml` file. Although this works in autotools,
the `.c` extension makes meson not to handle it properly.

Given the fact that it only contains a number of defines it
makes sense to change its extension to `.h` an use it as a header.
This also makes meson to handle it properly and build it before
its used.

https://mail.gnome.org/archives/networkmanager-list/2018-January/msg00057.html

Even Gentoo disables this plugin since before 0.9.8 release
of NetworkManager. Time to say goodbye.

If somebody happens to show up to maintain it, we may resurrect it
later.

If "$distro_plugins=ifnet" was set, configure.ac would use that
to autodetect --with-hostname-persist=gentoo. Replace that autodetect
part by checking for /etc/gentoo-release file.

Since meson 0.44 there is a new option type called `array`, which
allows to use an array with different values in those options.

These fits the needs of different options that are used to pass
binary paths, which have multiple paths as an alternate locations.

meson's version has been bumped to 0.44 and different options have
been changed to `array` type options.

https://mail.gnome.org/archives/networkmanager-list/2017-December/msg00062.html

meson is a build system focused on speed an ease of use, which
helps speeding up the software development. This patch adds meson
support along autotools.

[thaller@redhat.com: rebased patch and adjusted for iwd support]

https://mail.gnome.org/archives/networkmanager-list/2017-December/msg00022.html