ediff vs coding-system

[Stephen J. Turnbull]

Sean MacLennan writes:
 > The latest version of ediff (1.76, author version 2.75) seems to need a
 > coding-system called 'emacs-internal. Unfortunately, I don't seem to
 > have this in xemacs-21.4.21.
 > 
 > Anybody know where 'emacs-internal is defined?

It's the Mule internal coding system.  In XEmacs it can be elicited by
(a) compiling with --with-debug and (b) the "internal" coding system
IIRC.  But this is a very bad thing to expose to the rest of the
world.  I wonder why ediff uses it.