Remove duplicate XCB_EXTENSION calls for Composite extension
Remove duplicate XCB_EXTENSION calls for Composite extension

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