Re: [PATCH] verify: new macro 'assume'

[Paul Eggert]

Pádraig Brady wrote:
>> This minor point is becoming less important with time, as GCC
>> > 4.5-or-later will eventually become ubiquitous.
> Which might be an argument to take the simplest and most portable
> approach from this dwindling case.

Hmm, well, a downside is that it would cause verify.h
to include stdlib.h, which is a minor namespace hassle.
Similarly, having verify.h depend on NDEBUG entangles verify.h
with assert.h, another thing it's nicer to avoid.

Since this particular business is for --enable-gcc-warnings,
I'm not so much worried about the issues raised in the thread
you mentioned, as assume (COND) is by design not-debuggable-by-gdb if
COND is false -- that's how it works with newer GCC versions anyway,
and it'd be strange if we went to some effort to make it work differently
with older GCCs.

I also thought of defining our own extern inline function that never
returns, but that would mean we'd need a verify.c and this minor issue
with older GCCs didn't seem to be worth that much hassle.

I would have gladly removed the entire section in question (which would
be simpler yet), since I don't use the old GCCs -- but when I did
that in a related issue I got complaints from Emacs developers who
use old GCC versions with --enable-gcc-warnings and so I left
it in.  Maybe we can remove it in 2016 or so.  I could put in a
comment to that effect, if you like.