Except as provided in subsection (b) of this section or in other law, a contract to spend the proceeds of a general obligation loan that has been authorized by any act of the General Assembly may not be executed until the Board of Public Works approves the contract. Approval by the Board of Public Works is not required if the act merely authorizes a county or municipal corporation to borrow money and no State funds are involved. Approval by the Board of Public Works is not required for a contract or other authorization to spend the proceeds of a general obligation loan for public school construction projects.