* lang/cpp/src/global.h (ForceExtern, LocateExternal, KeyListModeMask):
New.
* lang/cpp/src/context.cpp (operator<<): Add check.
* lang/cpp/src/util.h (gpgme_keylist_mode_t,
convert_from_gpgme_keylist_mode_t): Handle ForceExtern.
* lang/cpp/tests/run-getkey.cpp (show_usage, main): Add arguments
--force-extern and --locate-external.
* lang/cpp/tests/run-keylist.cpp (show_usage, main): Ditto.