mention printing of warranty information in GUI programs

[Alfred M. Szmidt]

What do people think about this?

This aims to clarify that we prefer to have such information in both
--version, and in GUI programs.  This came up in a discussion on
emacs-devel.

--- standards.texi.~1.268.~     Thu Jul 30 22:34:33 2020
+++ standards.texi      Sun Oct 18 19:22:12 2020
@@ -3,7 +3,7 @@
 @setfilename standards.info
 @settitle GNU Coding Standards
 @c This date is automagically updated when you save this file:
-@set lastupdate June 12, 2020
+@set lastupdate October 18, 2020
 @c %**end of header
 
 @dircategory GNU organization
@@ -962,6 +962,11 @@
 screen readers (see
 @url{https://www.gnu.org/accessibility/accessibility.html}).  This should
 be automatic if you use GTK+.
+
+If your program is interactive, please also print the same information
+as for the @code{--version} option (@pxref{--version}) on program
+startup, and also provide instructions how to get more information
+about the copying conditions and warranty details.
 
 @node Command-Line Interfaces
 @section Standards for Command Line Interfaces