Snippets for amtk 5.6.1 from Alpine ppc64le

Sourced from https://build.alpinelinux.org/buildlogs/build-edge-ppc64le/community/amtk/amtk-5.6.1-r4.log.

• ../tests/interactive-tests/test-headerbar.c:186:9: warning: 'G_APPLICATION_FLAGS_NONE' is deprecated: Use 'G_APPLICATION_DEFAULT_FLAGS' instead [-Wdeprecated-declarations]
    186 |         app = gtk_application_new ("org.gnome.amtk.test-headerbar", G_APPLICATION_FLAGS_NONE);
        |         ^~~
  

• ../tests/interactive-tests/test-traditional-ui.c:203:9: warning: 'G_APPLICATION_FLAGS_NONE' is deprecated: Use 'G_APPLICATION_DEFAULT_FLAGS' instead [-Wdeprecated-declarations]
    203 |         app = gtk_application_new ("org.gnome.amtk.test-traditional-ui", G_APPLICATION_FLAGS_NONE);
        |         ^~~