Removed unused AtomicPtr::CompareAndSwap
issue-596: removed unused AtomicIncrement operation

There's no need for us to attempt to maintain Google's atomic ops code
in era of C++11.
issue-592: handle recent mingw with C++11 threads

Somehow it's c++ headers (like string) define pthread symbols without
even us asking for. That breaks old assumption that pthread symbols
are not available on windows.

In order to fix that we detect this condition in configure.ac and
avoid defining windows versions of pthread symbols.
fix compilation under VS 2013

This is essentially a copy of corresponding chromium change from:
https://codereview.chromium.org/27017003
don't re-define strtoq for VS2013

Which is part of previous change that wasn't correctly applied.
fix GCC version detect for platforms other than X86/X64
merge google rev 764d304