[Bug libstdc++/79190] [7 Regression] ld: (Warning) Unsatisfied symbol "aligned_alloc"

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79190

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to John David Anglin from comment #2)
> Looks as if the problem is here:
> 
> #else
> // The C library doesn't provide any aligned allocation functions, declare
> // aligned_alloc and get a link failure if aligned new is used.
> extern "C" void *aligned_alloc(std::size_t, std::size_t);
> #endif

Yep.

> Possibly, a better solution might be to provide an implementation that
> aborts.

Or throws std::bad_alloc to indicate failure to allocate:
https://gcc.gnu.org/ml/gcc-patches/2016-09/msg00578.html

But I think we can provide a fallback.