bug#25166: 26.0.50; It shouldn't be possible to set the function cell of nil and t

[Eli Zaretskii]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Mon, 26 Dec 2016 19:29:17 +0000
> Cc: 25166@debbugs.gnu.org
> 
>  And now see also ffb1302. :)
>  Anyway, I only did "nil", since as you say "t" can actually be called as
>  a function. But you are right that it's probably unintended.
> 
> Thanks! Interestingly the behavior was already added in 1994 (commit
> c15c5d408d696928862ca2848a359231e373556c), but apparently reverted later. I'd 
> suggest to simply
> reinstate that commit. 

It was reverted in 32e5c58ca969ec30d31520da52c9866cafa62927.  Perhaps
Stefan could tell why he did that (the log message doesn't say).