Macro gong::gong_option_set_fixed

macro_rules! gong_option_set_fixed {
    ( $long:tt, $short:tt, $mode:expr, $abbr:expr ) => { ... };
    ( $long:tt, $short:tt ) => { ... };
    () => { ... };
}

Construct an OptionSet

Takes:

1. An array of long options
2. An array of short options
3. Mode
4. Abbreviation support state

The last two can be left off if both defaults.

Example:

// Without modes, empty option lists
let _ = gong_option_set_fixed!([], []);
// With modes, empty option lists
let _ = gong_option_set_fixed!([], [], gong::options::OptionsMode::Standard, true);