anchor.diff:    mesaSupported =
       system == "i686-linux" ||
       system == "x86_64-linux";
  -  
  +
     mesa = assert mesaSupported; import ../development/libraries/mesa {
       inherit fetchurl stdenv pkgconfig x11 xlibs libdrm;
     };
  
positive.code:     texinfo = texinfo49;
    });
  
    # This new ghc stuff is under heavy development and will change ! 
    # ===============================================================
  
    # usage: see ghcPkgUtil.sh
    # depreceated -> use functions defined in builderDefs
    ghcPkgUtil = runCommand "ghcPkgUtil-internal" 
       { ghcPkgUtil = ../development/libraries/haskell/generic/ghcPkgUtil.sh; }
       "mkdir -p $out/nix-support; cp $ghcPkgUtil \$out/nix-support/setup-hook;";
  
  
negative.code:     inherit (stdenv.gcc) binutils libc;
      inherit stdenv;
    };
  
    g77_41 = import ../build-support/gcc-wrapper {
      name = "g77-4.1";
      nativeTools = false;
  