Previously, some of the doc comments for platform-independent APIs were
in `gdesktopappinfo.c`, which is only built on Unix systems. This meant
the introspection annotations for those APIs were not used on non-Unix
systems, which caused platform differences in `Gio-2.0.gir`.
So, move those doc comments to `gappinfo.c` and put them next to some
new platform-independent wrapper functions which provide a consistent
entry point and location for the API preconditions.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #3399
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
