+20220618
+ + add a null-pointer check for term_names field in copy_termtype(),
+ needed for MinGW port (report by Peiyuan Song, cf: 20220521).
+ + revise kon/kon2/jfbterm to undo "linux2.6" change to
+ smacs/rmacs/enacs (Debian #1012800) -TD
+ + amended note for att610+cvis0, as per documentation for att610,
+ att620, att730 -TD
+