[Bug libitm/63781] potential linkage issue with libitm.1.dylib

["howarth at bromo dot med.uc.edu" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63781

--- Comment #10 from howarth at bromo dot med.uc.edu ---
(In reply to Iain Sandoe from comment #9)
> (In reply to Francois-Xavier Coudert from comment #8)
> > As far as I understand, libitm is supposed to be used with either C or C++.
> > As such, it contains some C++ code which requires libstdc++, but doesn't
> > link to it by default. That way, if someone compiles C code with libitm, it
> > doesn't use need the C++ libitm code, and doesn't pull libstdc++. And when
> > one compiles C++ code, libstdc++ is linked in anyway, so it's no problem.
> > 
> > In short, I'm afraid I don't understand what you think the problem is :)
> > Do you have a "real" testcase that fails to link?
> 
> This is quite correct, as I pointed out to Jack before he opened the issue. 
> libitm weak links to the relevant symbols and uses them as required by the
> final program.

So the compiler will emit the ___cxa_tm_cleanup to resolve the undefined symbol
in libitm?