Function xkbcommon_sys::xkb_context_set_log_fn

pub unsafe extern "C" fn xkb_context_set_log_fn(
    context: *mut xkb_context, 
    log_fn: Option<unsafe extern "C" fn(context: *mut xkb_context, level: xkb_log_level, format: *const c_char, args: *mut __va_list_tag)>
)