(D) add_files_recursive, pass 2: explicitly ignoring ${MAIL_DIR}/one/two/ignored_file
(D) add_files_recursive, pass 2: explicitly ignoring ${MAIL_DIR}/one/two/three/.git
(D) add_files_recursive, pass 2: explicitly ignoring ${MAIL_DIR}/one/two/three/ignored_file
(D) add_files_recursive, pass 2: explicitly ignoring ${MAIL_DIR}/one/two/ignored_file
(D) add_files_recursive, pass 2: explicitly ignoring ${MAIL_DIR}/one/two/three/.git
(D) add_files_recursive, pass 2: explicitly ignoring ${MAIL_DIR}/one/two/three/ignored_file