N.C. Gen. Stat. § 117-22

In connection with the issuance of any bonds, a corporation may make covenants or agreements and do any and all acts or things that a business corporation can make or do under the laws of the State in order to secure its obligations or which, in the absolute discretion of the board, tend to make the obligations more marketable, notwithstanding that such covenants, agreements, acts and things may constitute limitations on the exercise of the powers herein granted.