https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63998
--- Comment #4 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
> If so, it would probably need
>
> // { dg-additional-options "-Wl,-undefined,dynamic_lookup" { target
> *-*-darwin* } }
> // { dg-additional-options "-Wl,-flat_namespace" { target *-*-darwin[89]* } }
>
> (see gcc.dg/attr-weakref-1.c).
>
> Untested so far.
It does not work because lto does not support dg-additional-options.
I confirm that adding -w to dg-lto-options fixes the failures. However I have
noticed that there is a lto_prune_warns in lib/lto.exp. It would probably
better to add
"warning: alias definitions not supported in Mach-O; ignored" to the list.
