Add SPDX license (but not copyright) headers to all files which follow a
certain pattern in their existing non-machine-readable header comment.
This commit was entirely generated using the command:
```
git ls-files gio/*.[ch] | xargs perl -0777 -pi -e 's/\n \*\n \* This library is free software; you can redistribute it and\/or\n \* modify it under the terms of the GNU Lesser General Public/\n \*\n \* SPDX-License-Identifier: LGPL-2.1-or-later\n \*\n \* This library is free software; you can redistribute it and\/or\n \* modify it under the terms of the GNU Lesser General Public/igs'
```
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #1415
The backend for this lives in xdg-desktop-portal,
and is in turn using GNetworkMonitor.
When network is not available in the sandbox, there is
no point in reporting accurately about the network
status outside the sandbox. Just return 'no connection'
in this case.
https://bugzilla.gnome.org/show_bug.cgi?id=768498