- All internal source files (except "examples", which are not internal)
should include "config.h" first. As also all internal source
files should include "nm-default.h", let "config.h" be included
by "nm-default.h" and include "nm-default.h" as first in every
source file.
We already wanted to include "nm-default.h" before other headers
because it might contains some fixes (like "nm-glib.h" compatibility)
that is required first.
- After including "nm-default.h", we optinally allow for including the
corresponding header file for the source file at hand. The idea
is to ensure that each header file is self contained.
- Don't include "config.h" or "nm-default.h" in any header file
(except "nm-sd-adapt.h"). Public headers anyway must not include
these headers, and internal headers are never included after
"nm-default.h", as of the first previous point.
- Include all internal headers with quotes instead of angle brackets.
In practice it doesn't matter, because in our public headers we must
include other headers with angle brackets. As we use our public
headers also to compile our interal source files, effectively the
result must be the same. Still do it for consistency.
- Except for <config.h> itself. Include it with angle brackets as suggested by
https://www.gnu.org/software/autoconf/manual/autoconf.html#Configuration-Headers
Split the content of libnm/nm-vpn-editor-plugin.h and
move NMVpnEditorPlugin to libnm-core/nm-vpn-editor-plugin.h.
VPN plugins allow us to extend functionality about VPNs.
This can be also useful for NetworkManager core, hence
move that part to libnm-core.
The name NMVpnEditorPlugin is slightly misleading but not completely
wrong. The "editor" part stands no longer for bringing nm-applet
functionality (alone), but enable general VPN functionality in
the client.
Especially because we already have NMVpnPluginOld with a different
meaning (i.e. a base class of the plugin server implementation).
