[RFC] COMDAT Safe Module Level Multi versioning

[Cary Coutant]

> Thanks, will make those changes.  Do you recommend a different name
> for this flag like -fmake-comdat-functions-static?

Well, the C++ ABI refers to this as "vague linkage." It may be a bit
too long or too ABI-specific, but maybe something like
-f[no-]use-vague-linkage-for-functions or
-f[no-]functions-vague-linkage?

And perhaps note in the doc that using this option may technically
break the C++ ODR, so it should be used only when you know what you're
doing.

-cary