[Bug target/62109] __gthr_i486_lock_cmp_xchg missing clobber

["ktietz at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62109

--- Comment #9 from Kai Tietz <ktietz at gcc dot gnu.org> ---
(In reply to David from comment #8)
> (In reply to Kai Tietz from comment #7)
> The first code block in comment #6 is what is in the code now.  As you can
> see, it already has the #define you are describing.  I don't understand what
> you mean by "change it to" this, since it is already there.
> 
> Are you suggesting we delete the entire #ifdef
> __GTHREAD_I486_INLINE_LOCK_PRIMITIVES block and replace it with the single
> #define? 
Right, this I suggest.

> I would be ok with that.  Using the #error (the second code block
> in comment #6) seemed like a more backward-compatible way to do this, since
> it would tell people what has happened and what to do to fix it rather than
> (silently) assuming we know what they want to do.

If a target doesn't provide the Interlocked-API, build with fail caused by it. 
I don't think we need to error out on such cases.  (We don't try to cover win
3.14 incompatibilities, so why we should start for Windows 9X?)

> But I am ok with either of these two solutions.