anchor.diff:      ++ optional stdenv.isDarwin Cocoa;
   
     buildInputs = [ libiconv ]
  +    ++ optionals (x11Support && stdenv.isDarwin) [ libXext libICE libXrandr ]
       ++ optional (!hostPlatform.isMinGW) audiofile
       ++ optionals stdenv.isDarwin [ AudioUnit CoreAudio CoreServices Kernel OpenGL ];
   
  
positive.code:   nativeBuildInputs = [ pkgconfig ];
  
    propagatedBuildInputs = [ ]
      ++ optionals x11Support [ libXext libICE libXrandr ]
      ++ optional stdenv.isLinux libcap
      ++ optionals openglSupport [ libGL libGLU ]
      ++ optional alsaSupport alsaLib
  
negative.code:     "--disable-oss"
      "--disable-video-x11-xme"
      "--enable-rpath"
    # Building without this fails on Darwin with
    #
    #   ./src/video/x11/SDL_x11sym.h:168:17: error: conflicting types for '_XData32'
    #   SDL_X11_SYM(int,_XData32,(Display *dpy,register long *data,unsigned len),(dpy,data,len),return)
    #
    # Please try revert the change that introduced this comment when updating SDL.
    ] ++ optional stdenv.isDarwin "--disable-x11-shared"
      ++ optional (!x11Support) "--without-x"
      ++ optional alsaSupport "--with-alsa-prefix=${attrs.alsaLib.out}/lib";
  
  in
  