anchor.diff:      libx11
       libxrandr
       libxrender
  -    mesa
  +    opengl-dummy
       renderproto
       systemd_lib
       wayland
  
positive.code:     "--enable-encoders"
      "--${boolEn (libdrm != null)}-drm"
      "--${boolEn (libx11 != null)}-x11"
      "--${boolEn (libx11 != null && mesa != null)}-glx"
      "--${boolEn (wayland != null)}-wayland"
      "--${boolEn (wayland != null && mesa != null)}-egl"
      "--disable-gtk-doc"
      "--disable-gtk-doc-html"
      "--disable-gtk-doc-pdf"
  
negative.code: , libx11
  , libxrandr
  , libxrender
  , opengl-dummy
  , renderproto
  , systemd_lib
  , wayland
  