Remove proto/X11 dependencies from xcb-demo.
Remove proto/X11 dependencies from xcb-demo.

OpenInkpot-archive/iplinux-libxcb,topcat/xcb-win32,topcat/xcb-win32,topcat/xcb-win32,stapelberg/libxcb,stapelberg/libxcb,topcat/xcb-win32,OpenInkpot-archive/iplinux-libxcb,OpenInkpot-archive/iplinux-libxcb,stapelberg/libxcb,topcat/xcb-win32