The problem we found in Gawk was that this sort of function call:
(b ? f : g) (x)
is mishandled by Clang < 16 when one function is _Noreturn and the other
isn't, in that Clang mistakenly treats the call as if both functions are
_Noreturn.
I expect this sort of issue to be reasonably rare in practical C code,
as most people don't write code like the above, and when they do then
typically F is _Noreturn if and only if G is also _Noreturn. So I've
held off on doing the more-drastic "#define _Noreturn /*empty*/" for
Clang < 16 in Gnulib, as my guess has been that the advantages of
enabling _Noreturn on Clang < 16 are greater than the disadvantages
given the rarity of situations like the above.
Of course I could be wrong....
