Don't detect X11 automagically
Don't detect X11 automagically

Instead, add an explicit --with-x11 option and default it to 'no'.
Based on a patch by Pacho Ramos, bug 657569.

djdeath/gdk-pixbuf,djdeath/gdk-pixbuf,GNOME/gdk-pixbuf,Distrotech/gdk-pixbuf,GNOME/gdk-pixbuf,YueLinHo/MB3Gdk-pixbuf,GNOME/gdk-pixbuf,djdeath/gdk-pixbuf,GNOME/gdk-pixbuf,YueLinHo/MB3Gdk-pixbuf,djdeath/gdk-pixbuf,YueLinHo/MB3Gdk-pixbuf,Distrotech/gdk-pixbuf,YueLinHo/MB3Gdk-pixbuf,Distrotech/gdk-pixbuf,YueLinHo/MB3Gdk-pixbuf,Distrotech/gdk-pixbuf,Distrotech/gdk-pixbuf