anchor.diff:      name = "xcb-proto-1.11";
       builder = ./builder.sh;
       src = fetchurl {
  -      url = http://xcb.freedesktop.org/dist/xcb-proto-1.11.tar.bz2;
  +      url = mirror://xorg/individual/xcb/xcb-proto-1.11.tar.bz2;
         sha256 = "0bp3f53l9fy5x3mn1rkj1g81aiyzl90wacwvqdgy831aa3kfxb5l";
       };
       nativeBuildInputs = [ python ];
  
positive.code:     name = "libxcb-1.11.1";
      builder = ./builder.sh;
      src = fetchurl {
        url = http://xcb.freedesktop.org/dist/libxcb-1.11.1.tar.bz2;
        sha256 = "0c4xyvdyx5adh8dzyhnrmvwwz24gri4z1czxmxqm63i0gmngs85p";
      };
      nativeBuildInputs = [ libxslt python ];
  
negative.code:     name = "xcb-util-wm-0.4.1";
      builder = ./builder.sh;
      src = fetchurl {
        url = mirror://xorg/individual/xcb/xcb-util-wm-0.4.1.tar.bz2;
        sha256 = "0gra7hfyxajic4mjd63cpqvd20si53j1q3rbdlkqkahfciwq3gr8";
      };
      nativeBuildInputs = [ gperf m4 xproto ];
  