message: fix std::put_time error on travis
diff: #include <stdlib.h>
  #include <chrono>
  #include <cstring>
  +#include <ctime>
  #include <iomanip>
  #include <sstream>
  #include <bsoncxx/oid.hpp>
  +#include <bsoncxx/private/libbson.hh>
  #include <bsoncxx/test_util/catch.hh>
  using namespace bsoncxx;
  @@ -40,6 +42,7 @@ parsed_oid parse_oid(const oid& oid) {
  std::memcpy(&parsed.rand, bytes + 1, 8);
  std::memcpy(&parsed.counter, bytes + 8, 4);
  +#if BSON_BYTE_ORDER != BSON_BIG_ENDIAN
  #ifndef _WIN32
  parsed.timestamp = __builtin_bswap32(parsed.timestamp);
  parsed.rand = __builtin_bswap64(parsed.rand) & 0x000000FFFFFFFFFF;
  @@ -48,15 +51,18 @@ parsed_oid parse_oid(const oid& oid) {
  parsed.timestamp = _byteswap_ulong(parsed.timestamp);
  parsed.rand = _byteswap_uint64(parsed.rand) & 0x000000FFFFFFFFFF;
  parsed.counter = _byteswap_ulong(parsed.counter) & 0x00FFFFFF;
  +#endif
  #endif
  return parsed;
  }
  void compare_string(const std::time_t& t, std::string time) {
  - std::stringstream time_stream;
  - time_stream << std::put_time(std::gmtime(&t), "%b %e, %Y %H:%M:%S UTC");
  - REQUIRE(time_stream.str() == time);
  + char time_str[48];
  +
  + REQUIRE(0 != (strftime(time_str, sizeof(time_str), "%b %e, %Y %H:%M:%S UTC", std::gmtime(&t))));
  +
  + REQUIRE(time_str == time);
  }
  TEST_CASE("oid", "[bsoncxx::oid]") {
  