[Bug lto/48200] linking shared library with LTO results in different exported symbols

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=48200

--- Comment #16 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Xi Ruoyao from comment #15)
> (In reply to Jan Hubicka from comment #13)
> > Concerning comment #11, if you have toplevel asms you need to disable LTO
> > for that unit, as there is no way to tell for gcc what the asm statement is
> > doing. Perhaps attribute would be better way to do this?
> 
> Well then this is PR 57703.   Should we mark duplicate? :(

I think the bug is sufficiently different and should have different
workarounds.

We might want to add a function attribute to allow to specify symver, so like

int pci_fill_info_v31(struct pci_dev *d, int flags)
__attribute__((alias("pci_fill_info"), symver("@LIBPCI_3.0"));

or similar (combine alias and symver as symver_alias?).  Or simply
recognize @ in alias.