case $THIS_SUB_DEPENDS in
  QT5) echo "QT5 support requested, forcing qtbase dependency." &&
     depends qtbase ''
     ;;
  XPDF_HEADERS) echo "XPDF_HEADERS requested, forcing -DENABLE_UNSTABLE_API_ABI_HEADERS=ON" &&
     list_add XPDF_HEADERS "-DENABLE_UNSTABLE_API_ABI_HEADERS=ON"
     ;;
  *) echo unknown sub-depends!!! ; return 1 ;;
esac