+20120324
+ + amend an old fix so that next_char() exits properly for empty files,
+ e.g., from reading /dev/null (cf: 20080804).
+ + modify tic so that it can read from the standard input, or from
+ a character device. Because tic uses seek's, this requires writing
+ the data to a temporary file first (prompted by remark by Sven
+ Joachim) (cf: 20000923).
+