No license shall be issued for the sale at retail of any alcoholic liquor within 100 feet of any church, school, hospital, home for aged or indigent persons or for veterans, their wives or children or any military or naval station; provided, that this prohibition shall not apply to clubs or to restaurants, food shops or other places where the sale of alcoholic liquor is not the principal business carried, if the place of business not exempted shall have been established for such purposes prior to the taking effect of this chapter. No person shall hereafter engage in business as a retailer of any alcoholic liquor within 100 feet of any undertaking establishment or mortuary.
(`70 Code, § 4-17)