depends pkgconfig

optional_depends libpng "--enable-png"   "--disable-png"   "For png graphics support"
optional_depends tiff   "--enable-tiff"  "--disable-tiff"  "For tiff graphics support"
optional_depends lcms2  "--enable-lcms2" "--disable-lcms2" "For lcms2 color management support"
optional_depends lcms   "--enable-lcms1" "--disable-lcms1" "For lcms1 color management support"
