Fix -fno-common build failure. Taken from https://github.com/awesomeWM/awesome/commit/d256d9055095f27a33696e0aeda4ee20ed4fb1a0 Index: objects/button.h --- objects/button.h.orig +++ objects/button.h @@ -39,7 +39,7 @@ typedef struct button_t xcb_button_t button; } button_t; -lua_class_t button_class; +extern lua_class_t button_class; LUA_OBJECT_FUNCS(button_class, button_t, button) ARRAY_FUNCS(button_t *, button, DO_NOTHING)