anchor.diff:  
     installPhase = installer nativeB2Args;
   
  -  outputs = [ "out" "lib" ];
  +  outputs = [ "out" "dev" "lib" ];
   
     crossAttrs = rec {
       buildInputs = [ expat.crossDrv zlib.crossDrv bzip2.crossDrv ];
  
positive.code:     # We want to substitute the contents of configureFlags, removing thus the
      # usual --build and --host added on cross building.
      preConfigure = ''
        export configureFlags="--prefix=$out --without-icu ${concatStringsSep " " commonConfigureFlags}"
        set -x
        cat << EOF > user-config.jam
        using gcc : cross : $crossConfig-g++ ;
  
negative.code: 
    installer = b2Args: ''
      # boostbook is needed by some applications
      mkdir -p $dev/share/boostbook
      cp -a tools/boostbook/{xsl,dtd} $dev/share/boostbook/
  
      # Let boost install everything else
      ./b2 ${b2Args} install
  
      # Create a derivation which encompasses everything, making buildInputs nicer
      mkdir -p $out/nix-support
      echo $dev >> $out/nix-support/propagated-build-inputs
      echo $lib >> $out/nix-support/propagated-build-inputs
    '';
  
    commonConfigureFlags = [
  