ci: Use libadwaita from git

build-aux/install_deps.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+set -e
+
+echo "===== Install GTK ====="
+git clone --depth=1 https://gitlab.gnome.org/GNOME/gtk.git
+cd gtk
+meson setup builddir \
+  --prefix=/usr \
+  -Dgtk_doc=true \
+  -Ddemos=false \
+  -Dbuild-examples=false \
+  -Dbuild-tests=false \
+  -Dbuild-testsuite=false
+ninja -C builddir install
+cd -
+rm -rf gtk
+
+echo "===== Install libadwaita ====="
+git clone --depth=1 https://gitlab.gnome.org/GNOME/libadwaita.git
+cd libadwaita
+meson builddir \
+  --prefix=/usr
+ninja -C builddir install
+cd -
+rm -rf libadwaita