//! The operating system.

    //! The compiling operating system.

    //! The compiling operating system's version.
    /*!
     * Specifies the version of the OS that the executable was compiled on.
     */
    std::string BuildOSVersion();

    }
    std::string BuildOSVersion()
    {
        return CRAWL_BUILD_OS_VER;

    out += make_stringf("Compiled on OS: %s" EOL,
                        Version::BuildOS().c_str());

    out += make_stringf("Compiled on OS: %s %s" EOL,
                        Version::BuildOS().c_str(),
                        Version::BuildOSVersion().c_str());