Whenever the board of county commissioners of any county considers it to be to the best interest of the county to acquire sites, purchase, erect, repair, remodel, equip and furnish a courthouse or jail, they shall have power to contract for the acquisition of sites, purchase, erection, repair, remodeling, equipping and furnishing of same and to issue bonds in payment therefor. Provided, however, that the bonds shall not be issued until the question shall have first been submitted to the people of the county and a three-fifths ( ³/₅ ) majority of the qualified voters voting at any general election, or special election called by the board of county commissioners for the purpose, shall have declared by their votes in favor of issuing such bonds.