[PATCH B2/2] Use builtin_unreachable in assert

[Roland McGrath]

> > "No side effects" at the C level certainly does not
> > preclude a different correct translation of the program to machine code.
> 
> sure ... i wasn't saying otherwise.  my point is that __builtin_unreachable 
> doesn't do that -- it explicitly is documented by gcc as:
>   If control flow reaches the point of the __builtin_unreachable, the program is 
>   undefined.
> 
> if there was a solution as Richard alluded to that allows for expansion of the 
> expression all the time w/out breaking things when the assert is actually hit, 
> i'm all for that.

I don't understand what your concern is.  A call to __assert_fail leads to
a call to abort and that is no more or less well-defined or recoverable
than __builtin_unreachable.