RE_NO_POSIX_BACKTRACKING  170 lib/regex.h    # define RE_NO_POSIX_BACKTRACKING (RE_UNMATCHED_RIGHT_PAREN_ORD << 1)
RE_NO_POSIX_BACKTRACKING  140 test/manual/etags/c-src/emacs/src/regex.h #define RE_NO_POSIX_BACKTRACKING (RE_UNMATCHED_RIGHT_PAREN_ORD << 1)