Emacs is not only on GTK. I doubt any indispensable core components will depend on xwidgets unless it can embed each toolkit emacs can use. Further, customize

Emacs is not only on GTK. I doubt any indispensable core components will depend on xwidgets unless it can embed each toolkit emacs can use. Further, customize is used on the terminal emulator and on the framebuffer too, having it require X is not feasible.