anchor.diff:  
     # move gallium-related stuff to $drivers, so $out doesn't depend on LLVM;
     #   also move libOSMesa to $osmesa, as it's relatively big
  -  # ToDo: probably not all .la files are completely fixed, but it shouldn't matter
  +  # TODO: probably not all .la files are completely fixed, but it shouldn't matter
     postInstall = /* Remove vendored Vulkan headers */ ''
       rm -fv $out/include/vulkan/vk_platform.h
       rm -fv $out/include/vulkan/vulkan.h
  
positive.code: , flex
  , gettext
  , intltool
  , python2Packages
  
  , dri2proto
  
negative.code:   '' + /* work around bug #529, but maybe $drivers should also be patchelf'd */ ''
      find $drivers/ $osmesa/ -type f -executable -print0 | \
        xargs -0 strip -S || true
    '' + /* add RPATH so the drivers can find the moved libgallium & libdricore9 */ ''
      for lib in $drivers/lib/*.so* $drivers/lib/*/*.so*; do
        if [[ ! -L "$lib" ]] ; then
          patchelf \
  