anchor.diff:    # Zlib and OpenSSL must be propagated because `libcurl.la' contains
     # "-lz -lssl", which aren't necessary direct build inputs of
     # applications that use Curl.
  -  propagatedBuildInputs =
  -    stdenv.lib.optional zlibSupport zlib ++
  -    stdenv.lib.optional sslSupport openssl;
  +  propagatedBuildInputs = with stdenv.lib;
  +    optional zlibSupport zlib ++
  +    optional gssSupport gss ++
  +    optional sslSupport openssl;
   
  -  configureFlags = ''
  -    ${if sslSupport then "--with-ssl=${openssl}" else "--without-ssl"}
  -    ${if scpSupport then "--with-libssh2=${libssh2}" else "--without-libssh2"}
  -    ${if linkStatic then "--enable-static --disable-shared" else ""}
  +  preConfigure = ''
  +    sed -e 's|/usr/bin|/no-such-path|g' -i.bak configure
     '';
  +  configureFlags = [
  +      ( if sslSupport then "--with-ssl=${openssl}" else "--without-ssl" )
  +      ( if scpSupport then "--with-libssh2=${libssh2}" else "--without-libssh2" )
  +    ]
  +    ++ stdenv.lib.optional gssSupport "--with-gssapi=${gss}"
  +    ++ stdenv.lib.optionals linkStatic [ "--enable-static" "--disable-shared" ]
  +  ;
   
     dontDisableStatic = linkStatic;
   
  
positive.code:   crossAttrs = {
      # We should refer to the cross built openssl
      # For the 'urandom', maybe it should be a cross-system option
      configureFlags = ''
        ${if sslSupport then "--with-ssl=${openssl.crossDrv}" else "--without-ssl"}
        ${if linkStatic then "--enable-static --disable-shared" else ""}
        --with-random /dev/urandom
      '';
    };
  
    passthru = {
      inherit sslSupport openssl;
    };
  
    preConfigure = ''
      sed -e 's|/usr/bin|/no-such-path|g' -i.bak configure
    '';
  
    meta = {
      homepage = "http://curl.haxx.se/";
      description = "A command line tool for transferring files with URL syntax";
  
negative.code: , zlibSupport ? false, zlib ? null
  , sslSupport ? false, openssl ? null
  , scpSupport ? false, libssh2 ? null
  , gssSupport ? false, gss ? null
  , linkStatic ? false
  }:
  
  