"nm-macros-interal.h" already includes <errno.h> and <string.h>.
No need to include it everywhere else too.

The D-Bus path is a useful property, also exposed via
nm_object_get_path() function. Don't mark it to be
skipped from documentation and introspection.

This was changed in "1f5b48a59e libnm: use the o.fd.DBus.ObjectManager
API for object management" and was an API breakage of libnm.
This also caused a bug in gnome-shell [1].

[1] https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/240/diffs
[2] https://bugzilla.redhat.com/show_bug.cgi?id=1628263

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/merge_requests/16

Fixes: 1f5b48a59eb46c40cb10bf4381b2b21a19a9f471

Remainder of typos found using `codespell -q 3 --skip="./shared,./src/systemd,*.po" -I ../NetworkManager-word-whitelist.txt` whereby whitelist consists of:
 ```
ans
busses
cace
cna
conexant
crasher
iff
liftime
creat
nd
sav
technik
uint
```

https://github.com/NetworkManager/NetworkManager/pull/205

We commonly don't use the glib typedefs for char/short/int/long,
but their C types directly.

    $ git grep '\<g\(char\|short\|int\|long\|float\|double\)\>' | wc -l
    587
    $ git grep '\<\(char\|short\|int\|long\|float\|double\)\>' | wc -l
    21114

One could argue that using the glib typedefs is preferable in
public API (of our glib based libnm library) or where it clearly
is related to glib, like during

  g_object_set (obj, PROPERTY, (gint) value, NULL);

However, that argument does not seem strong, because in practice we don't
follow that argument today, and seldomly use the glib typedefs.
Also, the style guide for this would be hard to formalize, because
"using them where clearly related to a glib" is a very loose suggestion.

Also note that glib typedefs will always just be typedefs of the
underlying C types. There is no danger of glib changing the meaning
of these typedefs (because that would be a major API break of glib).

A simple style guide is instead: don't use these typedefs.

No manual actions, I only ran the bash script:

  FILES=($(git ls-files '*.[hc]'))
  sed -i \
      -e 's/\<g\(char\|short\|int\|long\|float\|double\)\>\( [^ ]\)/\1\2/g' \
      -e 's/\<g\(char\|short\|int\|long\|float\|double\)\>  /\1   /g' \
      -e 's/\<g\(char\|short\|int\|long\|float\|double\)\>/\1/g' \
      "${FILES[@]}"

Coccinelle:

  @@
  expression a, b;
  @@
  -a ? a : b
  +a ?: b

Applied with:

  spatch --sp-file ternary.cocci --in-place --smpl-spacing --dir .

With some manual adjustments on spots that Cocci didn't catch for
reasons unknown.

Thanks to the marvelous effort of the GNU compiler developer we can now
spare a couple of bits that could be used for more important things,
like this commit message. Standards commitees yet have to catch up.

Use the one from the project just imported.

If an operation is cancelled through the GCancellable, then the idiom is
that the operation is always cancelled, even if it has finished
successfully. To ensure this is the case, add calls to
g_simple_async_result_set_check_cancellable everywhere.

Without this, e.g. gnome-control-center will crash when switching away
from the power panel quickly, as the NMClient creation finishes
asynchronously and g-c-c assume that G_IO_ERROR_CANCELLED is returned to
ensure it doesn't access the now invalid user_data parameter.

https://bugzilla.gnome.org/show_bug.cgi?id=794088

XXX was used to either raise attention (NOTE) or to indicate
that this is ugly code that should be fixed (FIXME). The usage
was inconsistent.

Let's avoid XXX and use either NOTE or FIXME.