optional_argument  333 maint/gnulib/lib/argp-parse.c                           ? optional_argument
optional_argument   40 maint/gnulib/tests/test-getopt_long.h     { "prune",    optional_argument, NULL, 'p' },
optional_argument   41 maint/gnulib/tests/test-getopt_long.h     { "quetsche", optional_argument, &q_seen, 1 },