xfce4-panel 4.20.1 fails to build with glib < 2.84.0
When building against glib-2.82.4:
panel-plugin-external-wrapper-exported.c: In function ‘xfce_panel_plugin_wrapper_exported_skeleton_dbus_interface_get_properties’:
panel-plugin-external-wrapper-exported.c:1564:33: warning: "GLIB_VERSION_2_84" is not defined, evaluates to 0 [-Wundef]
1564 | #if GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_84
| ^~~~~~~~~~~~~~~~~
panel-plugin-external-wrapper-exported.c:1565:3: error: implicit declaration of function ‘g_variant_builder_init_static’; did you mean ‘g_variant_builder_init’? [-Wimplicit-function-declaration]
1565 | g_variant_builder_init_static (&builder, G_VARIANT_TYPE ("a{sv}"));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| g_variant_builder_init
panel-plugin-external-wrapper-exported.c:1565:3: warning: nested extern declaration of ‘g_variant_builder_init_static’ [-Wnested-externs]
panel-gdbus-exported-service.c: In function ‘xfce_panel_exported_service_skeleton_dbus_interface_get_properties’:
panel-gdbus-exported-service.c:2273:33: warning: "GLIB_VERSION_2_84" is not defined, evaluates to 0 [-Wundef]
2273 | #if GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_84
| ^~~~~~~~~~~~~~~~~
panel-gdbus-exported-service.c:2274:3: error: implicit declaration of function ‘g_variant_builder_init_static’; did you mean ‘g_variant_builder_init’? [-Wimplicit-function-declaration]
2274 | g_variant_builder_init_static (&builder, G_VARIANT_TYPE ("a{sv}"));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| g_variant_builder_init
panel-gdbus-exported-service.c:2274:3: warning: nested extern declaration of ‘g_variant_builder_init_static’ [-Wnested-externs]