Notwithstanding the provisions of existing law, except the Commodity Credit Corporation Charter Act [15 U.S.C. 714 et seq.] and without regard to sections 3111 and 3112 of title 40, but within the limitations of cost otherwise applicable, appropriations of the Department of Agriculture may be expended for the erection of buildings and other structures on land owned by States, counties, municipalities, or other political subdivisions, corporations, or individuals: Provided