r194095 - Produce direct calls instead of alias to linkonce_odr functions.

[Rafael Espíndola]

>> Do any of the .o files were produced
>> by clang [
>> 194000,r194095)?
>
>
> Not in a ready-for-test-case form.
>
> This still seems like it is fundamentally breaking ABI with old clang
> versions, and potentially with GCC.

GCC compatibility was not affected, since it uses comdat names we are
not even able to represent now.
This change brings compatibility with 193999. It was 194000 that could
have introduce comdats with two symbols in a comdat. Both <= 193999
and current should have only one symbol per comdat.

> I'm not sure we should do this, and I
> would like to not do this without some lead time to test it out. Certainly,
> it is currently blocking everything we do with Clang internally, literally
> everything is broken. =[ Can you at least go back to emitting the weak_odr
> alias so that link steps which rely on this continue to work?

For the above reason if we revert at all we should revert all the way
back to not using alias for this.

Cheers,
Rafael