adwaita-icon-theme-legacy: init at 46.2

This theme contains icons required by icon-naming-spec that were removed from Adwaita icon theme proper few releases back.
Try installing it in addition to `gnome.adwaita-icon-theme` if some apps are missing icons.
See https://gitlab.gnome.org/GNOME/adwaita-icon-theme/-/issues/288 for more info.

Signed-off-by: John Titor <50095635+JohnRTitor@users.noreply.github.com>

pkgs/by-name/ad/adwaita-icon-theme-legacy/package.nix

@@ -0,0 +1,39 @@
+{
+  lib,
+  stdenv,
+  fetchurl,
+  meson,
+  ninja,
+  gtk4,
+  gnome,
+}:
+
+stdenv.mkDerivation (finalAttrs: {
+  pname = "adwaita-icon-theme-legacy";
+  version = "46.2";
+
+  src = fetchurl {
+    url = "mirror://gnome/sources/adwaita-icon-theme-legacy/${lib.versions.major finalAttrs.version}/adwaita-icon-theme-legacy-${finalAttrs.version}.tar.xz";
+    hash = "sha256-VISA9YWJpUty0Ygzt1WxX/vVZ+MYcknXTi4fj5nyL7Q=";
+  };
+
+  nativeBuildInputs = [
+    meson
+    ninja
+    gtk4 # for gtk4-update-icon-cache
+  ];
+
+  passthru = {
+    updateScript = gnome.updateScript {
+      packageName = "adwaita-icon-theme-legacy";
+    };
+  };
+
+  meta = with lib; {
+    description = "Fullcolor icon theme providing fallback for legacy apps";
+    homepage = "https://gitlab.gnome.org/GNOME/adwaita-icon-theme-legacy";
+    license = licenses.cc-by-sa-30;
+    maintainers = teams.gnome.members;
+    platforms = platforms.all;
+  };
+})