[m-rev.] for-review: Apply upstream BoehmGC changes for glibc lock elision bug workaround

[Julien Fischer]

On Thu, 18 Sep 2014, Paul Bone wrote:

> For review/testing by others.
>
> Last time I modified something in boehm_gc/ I broke the build for OS X.
> This works on 64bit Linux (Debian testing) but I havn't tested it on other
> platforms.  Julien could you help me out by building this on OS X and
> perhaps Windows?  I've been testing it with the icfp2000_par_pbone benchmark
> in asm_fast.gc.par.stseg.  Thanks.
>
> I have a branch with these patches here:
> https://github.com/PaulBone/mercury/tree/fix_tsx_bug

Ok, I'll take a look at it on those systems, but probably not today.
(The above benchmark won't work on OS X in any case.)

Cheers,
Julien.