case $THIS_SUB_DEPENDS in
  QT4) echo "QT4 support requested, forcing qt4 dependency." &&
     depends -sub TOOLS qt4 '--enable-poppler-qt4'
     ;;
  XPDF_HEADERS) echo "XPDF_HEADERS requested, forcing --enable-xpdf-headers" &&
     list_add POPPLER_OPTS --enable-xpdf-headers &&
     list_remove POPPLER_OPTS --disable-xpdf-headers
     ;;
  *) echo unknown sub-depends!!! ; return 1 ;;
esac