bug#3984: bug#123: Potential fix

[Ryan]

Dear all,

I "fixed" this in my ido-ubiquitous package by completely reimplementing 
"called-interactively-p" and "interactive-p" in pure elisp: 
https://github.com/DarwinAwardWinner/ido-ubiquitous/commit/f0c42e289a614071e22ad2c08297a7ebd60ba1cc

Apart from simply translating the C code in elisp, I made two key 
adjustments to the logic: first, I filter out all evidence of advice 
from the call stack before checking if the caller is 
"call-interactively". Second, I relax the definition of "caller is 
call-interactively" to include any symbol with the same 
"symbol-function" as call-interactively, or any function that is the 
same as the symbol-function of call-interactively. Combined, these 
adjustments mean that defining advice on call-interactively no longer 
results in erroneous return values from these two interactivity-testing 
functions.

I have implemented this in elisp because that is the only way to 
redefine functions in a running emacs session, but there's no reason 
that the C code couldn't be adapted to use the same logic.

-Ryan