anchor.diff:      ++ optionals sdlSupport [ SDL2 ]
       ++ optionals gtkSupport [ gtk3 gettext gnome3.vte ]
       ++ optionals vncSupport [ libjpeg libpng ]
  +    ++ optionals smartcardSupport [ libcacard ]
       ++ optionals spiceSupport [ spice-protocol spice ]
       ++ optionals usbredirSupport [ usbredir ]
       ++ optionals stdenv.isLinux [ alsaLib libaio libcap_ng libcap attr ]
  
positive.code:     ++ optional stdenv.isDarwin "--cpu=x86_64"
      ++ optional numaSupport "--enable-numa"
      ++ optional seccompSupport "--enable-seccomp"
      ++ optional spiceSupport "--enable-spice"
      ++ optional usbredirSupport "--enable-usb-redir"
      ++ optional hostCpuOnly "--target-list=${hostCpuTargets}"
  
negative.code: , sdlSupport ? !stdenv.isDarwin, SDL2
  , gtkSupport ? !stdenv.isDarwin && !xenSupport, gtk3, gettext, gnome3
  , vncSupport ? true, libjpeg, libpng
  , smartcardSupport ? true, libcacard
  , spiceSupport ? !stdenv.isDarwin, spice, spice-protocol
  , usbredirSupport ? spiceSupport, usbredir
  , xenSupport ? false, xen
  