Function gifski::c_api::gifski_new

#[no_mangle]
pub unsafe extern "C" fn gifski_new(
    settings: *const GifskiSettings
) -> *const GifskiHandle

Call to start the process

See gifski_add_frame_png_file and gifski_end_adding_frames

Returns a handle for the other functions, or NULL on error (if the settings are invalid).