All personnel actions affecting employees or applicants for employment (except with regard to aliens employed outside the limits of the United States) in military departments as defined in section 102 of title 5, in executive agencies as defined in section 105 of title 5 (including employees and applicants for employment who are paid from nonappropriated funds), in the United States Postal Service and the Postal Regulatory Commission, in those units of the Government of the District of Columbia having positions in the competitive service, and in those units of the judicial branch of the Federal Government having positions in the competitive service, in the Smithsonian Institution, and in the Government Publishing Office, the Government Accountability Office, and the Library of Congress shall be made free from any discrimination based on race, color, religion, sex, or national origin.