optional_depends %OSSL         "--with-ssl"      "--without-ssl"      "for ssl support"
optional_depends libusb-compat "--with-usb"      "--without-usb"      "for usb support"
optional_depends net-snmp      "--with-snmp"     "--without-snmp"     "for snmp support"
optional_depends neon          "--with-neon"     "--without-neon"     "for XML/HTTP support"
optional_depends avahi         "--with-avahi"    "--without-avahi"    "for avahi support"
