anchor.diff:      "--enable-asm"
       # TODO: selinux support
       "--disable-selinux"
  +    "--enable-llvm-shared-libs"
       "--enable-opengl"
       "--enable-gles1"
       "--enable-gles2"
  
positive.code: 
    postPatch = ''
      patchShebangs .
    '' + /* Set runtime driver search path */ ''
      sed -i src/egl/main/egldriver.c \
        -e 's,_EGL_DRIVER_SEARCH_DIR,"${driverSearchPath}",'
    '' + /* Upstream incorrectly specifies PYTHONPATH explicitly, overriding
            the build environments PYTHONPATH */ ''
      sed -e 's,PYTHONPATH=,PYTHONPATH=$(PYTHONPATH):,g' \
        -i src/mesa/drivers/dri/i965/Makefile.am \
  
negative.code:     "--enable-gallium-extra-hud"
      "--enable-lmsensors"
      "--enable-dri3"
      "--enable-glx"  # dri|xlib|gallium-xlib
      "--disable-osmesa"
      "--enable-gallium-osmesa"
      "--enable-egl"
  