The powers conferred by this Act shall be in addition and supplemental to, and not in substitution for, the powers conferred by any other law, and may be exercised in conjunction with such powers conferred by other laws, and no restrictions or limitations upon the powers of the Board of Trustees of the University of Illinois contained in Section 1 of this Act shall be applicable in the case of any leases, contracts or undertakings entered into by such Board relating to the construction, use or operation of any building erected by the University of Illinois Building Commission under and pursuant to any Act creating such a Commission.