/// engine_name() returns the full name of the current Glaurung version.
/// This will be either "Glaurung YYMMDD" (where YYMMDD is the date when the
/// program was compiled) or "Glaurung <version number>", depending on whether
/// engine_name() returns the full name of the current Glaurung version.
/// This will be either "Glaurung YYMMDD" (where YYMMDD is the date when the
/// program was compiled) or "Glaurung <version number>", depending on whether