message: build: improve macro for testing -latomic requirement
diff: @@ -12,11 +12,17 @@ dnl warranty.
  m4_define([_CHECK_ATOMIC_testbody], [[
  #include <atomic>
  #include <cstdint>
  + #include <chrono>
  +
  + using namespace std::chrono_literals;
  int main() {
  std::atomic<bool> lock{true};
  std::atomic_exchange(&lock, false);
  + std::atomic<std::chrono::seconds> t{0s};
  + t.store(2s);
  +
  std::atomic<int64_t> a{};
  int64_t v = 5;
  