* Use base_internal::AtomicHook instead of std::atomic

std::atomic has a broken implementation on the Windows platform and it
is not conform to the ABSL_CONST_INIT macro when clang-cl is used as a
compiler: the macro is expanded to the [[clang::require_constant_initialization]]
attribute and the attribute cannot be applied to the broken std::atomic.

Therefore, std::atomic has been replaced with absl::base_internal::AtomicHook
to fix the compilation error (thank Derek Mauro for the suggestion).

Issue: #659

Signed-off-by: Pavel Samolysov <samolisov@gmail.com>

* Update build files for pull request

Co-authored-by: Derek Mauro <dmauro@google.com>