bug#20202: bug#20484: bug#20202: Considered Harmful 73d213: 'Comint, term, and compile new set Emacs'

[Paul Eggert]

Phillip Lord wrote:
> They've just patched SWI-Prolog to look at INSIDE_EMACS anyway.

Amusingly enough, the SWI-Prolog implementation (both unpatched and patched) 
disagrees with its documentation, which says SWI-Prolog assumes it is running 
under Emacs "if the environment variable EMACS is 't' and INFERIOR is 'yes'."

Note the restriction to 't' in the documentation (which the code does not 
enforce). Note also the "and" in the documentation (the code uses "||").

It sounds like this stuff isn't exercised much....

> I'm guessing that anyone who wants the EMACS=t behaviour should be able to
> get it back by adding (setenv "EMACS" "t") to their .emacs?

Yes, that works. Or in practice for SWI-Prolog (setenv "INFERIOR" "yes") should 
also do the trick.