Index: cmake/modules/CheckAtomic64.cmake
===================================================================
--- /dev/null
+++ cmake/modules/CheckAtomic64.cmake
@@ -0,0 +1,38 @@
+INCLUDE(CheckCXXSourceCompiles)
+
+# To ensure libatomic get link for 64 bit atomic operations.
+
+function(check_cxx_atomics varname)
+  set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
+  set(CMAKE_REQUIRED_FLAGS "-std=c++11 ${CMAKE_REQUIRED_FLAGS}")
+  check_cxx_source_compiles("
+#include <atomic>
+#include <cstdint>
+std::atomic<uint64_t> x (0);
+int main() {
+  uint64_t i = x.load(std::memory_order_relaxed);
+  return 0;
+}
+" ${varname})
+  set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
+endfunction(check_cxx_atomics)
+
+if(MSVC)
+    set(HAVE_CXX_ATOMIC64_WITHOUT_LIB True)
+else()
+    check_cxx_atomics(HAVE_CXX_ATOMIC64_WITHOUT_LIB)
+endif()
+
+# If not, check if the library exists, and atomics work with it.
+if(NOT HAVE_CXX_ATOMIC64_WITHOUT_LIB)
+  check_library_exists(atomic __atomic_load_8 "" HAVE_CXX_LIBATOMIC64)
+  if(HAVE_CXX_LIBATOMIC64)
+    list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic")
+    check_cxx_atomics(HAVE_CXX_ATOMIC64_WITH_LIB)
+    if (NOT HAVE_CXX_ATOMIC64_WITH_LIB)
+      message(FATAL_ERROR "Host compiler must support std::atomic!")
+    endif()
+  else()
+    message(FATAL_ERROR "Host compiler appears to require libatomic, but cannot find it.")
+  endif()
+endif()