libstdc++ and race detectors

[Paolo Carlini]

... in the meanwhile I actually had a look to the referenced web page.

Apparently, this is a kind of change which we *can* do, because it
entirely lives in an header, static inline, and I think should not cause
problems for the ABI (in the wide-sense). Good news ;)

Thus I would suggest trying to come up with a full patch, touching
atomicity.h essentially, and then adjusting consistently all the callers
everywhere. Note: all the names must be uglified, thus __refcount,
__res. Also, something like - note single underscore in front, no
underscores at the end - _GLIBCXX_HAPPENS_AFTER, etc., maybe better
adding something to the name mentioning atomicity & co.

Paolo.