Boy this was hard.
To ease the pain of porting wireless-security to GTK4, add
a new WsFileChooserButton class that mimics the behavior of
a button that triggers a filechooser, as per the migration
guide suggests.
There were lots of GtkGrids, so the diff is particularly
horrendous. Sorry.
This needs serious testing before landing.
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.
https://bugzilla.gnome.org/show_bug.cgi?id=785414
