[Bug c++/81668] LTO ODR warnings are not helpful

["sgunderson at bigfoot dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81668

--- Comment #9 from sgunderson at bigfoot dot com ---
(In reply to Manuel López-Ibáñez from comment #8)
> Actually, what would be more useful is to detect that the difference in type
> comes from S and point out where S has been declared as different types.

Yes, that would be even better. But save for that :-)

> Note that this is not the same bug I pointed out for 
> 
> ../include/violite.h:288:8: warning: type ‘struct st_vio’ violates the C++
> One Definition Rule [-Wodr]
> ../include/violite.h:288:0: note: a different type is defined in another
> translation unit
> 
> The :0: indicates something wrong with the location info. If the location is
> unknown, it would be better to use UNKNOWN_LOCATION.

Yes, I know. It's a bit odd, but it doesn't bother me as much in this case.