prev_prev_backslash 3071 libglibc/regex.c   boolean prev_prev_backslash = prev > pattern && prev[-1] == '\\';
prev_prev_backslash 3075 libglibc/regex.c        (*prev == '(' && (syntax & RE_NO_BK_PARENS || prev_prev_backslash))
prev_prev_backslash 3077 libglibc/regex.c     || (*prev == '|' && (syntax & RE_NO_BK_VBAR || prev_prev_backslash));