[Bug sanitizer/78307] [7 Regression] missing symbols in libubsan without changing the soname

["m.ostapenko at samsung dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78307

--- Comment #6 from Maxim Ostapenko <m.ostapenko at samsung dot com> ---
(In reply to Jakub Jelinek from comment #5)
> (In reply to Maxim Ostapenko from comment #4)
> > But LLVM doesn't support shared UBSan runtime (the only one supported is
> > ASan) and AFAIK there aren't any plans to support it there.
> 
> Yeah, it is a very weird policy.
> 
> > > In any case, we shouldn't be making ABI incompatible changes in the
> > > libraries.  So, either we should bump soname, or preferably, if it is not
> > > that hard to readd those symbols, just do that, so that people don't have to
> > > fight yet another changed library.
> > 
> > Do you mean we can apply a local patch?
> 
> We can, sure.

Ok, I think I can just add (perhaps empty?) stubs into libubsan to readd those
symbols, this should be quite trivial.