anchor.diff:  { stdenv, fetchurl, perl, gnum4, ncurses, openssl
   , gnused, gawk, makeWrapper
   , odbcSupport ? false, unixODBC ? null
  -, wxSupport ? true, mesa ? null, wxGTK ? null, xlibs ? null
  +, wxSupport ? true, mesa ? null, wxGTK ? null, xlibs ? null, wxmac ? null
   , javacSupport ? false, openjdk ? null
  -, enableHipe ? true}:
  +, enableHipe ? true
  +}:
   
  -assert wxSupport -> mesa != null && wxGTK != null && xlibs != null;
  +assert wxSupport -> (if stdenv.isDarwin
  +  then wxmac != null
  +  else mesa != null && wxGTK != null && xlibs != null);
  +
   assert odbcSupport -> unixODBC != null;
   assert javacSupport ->  openjdk != null;
   
  
positive.code:     sed -e s@/bin/pwd@pwd@g -i otp_build
    '';
  
    configureFlags= "--with-ssl=${openssl} ${optionalString enableHipe "--enable-hipe"} ${optionalString odbcSupport "--with-odbc=${unixODBC}"} ${optionalString stdenv.isDarwin "--enable-darwin-64bit"} ${optionalString javacSupport "--with-javac"}";
  
    postInstall = let
      manpages = fetchurl {
  
negative.code: 
    buildInputs =
      [ perl gnum4 ncurses openssl makeWrapper
      ] ++ optional wxSupport (if stdenv.isDarwin then [ wxmac ] else [ mesa wxGTK xlibs.libX11 ])
        ++ optional odbcSupport [ unixODBC ]
        ++ optional javacSupport [ openjdk ];
  
  