Considered Harmful 73d213: "Comint, term, and compile new set Emacs"

[Phillip Lord]

I've just found commit 73d213 has been added, which restores the
$EMACS behaviour in comint, shell and compile. In other words $EMACS
gets set to "t".

Unfortunately, this affects both cask and ert-runner which I had altered
to take account of and depend on the new behaviour for Emacs-25. In this
case, cask and ert-runner use $EMACS to mean "the location of the Emacs
to run". This will require explicit setting now.

In an truly entertaining piece of irony, my fixes to cask and ert-runner
were merged on 23 Mar, the same day as commit 73d213, which breaks the
fixes.

Not sure how to fix this, but the commentary prior to commit beaab89
says "we are going to rid of this binding, probably in Emacs 23". It
seems a shame to be three major versions wrong.

Phil