message: fix compile if OS doesn't support IPV6_TRANSPARENT
diff: @@ -111,7 +111,7 @@ bool OsSysCallsImpl::supportsUdpGso() const {
  }
  bool OsSysCallsImpl::supportsIpTransparent() const {
  -#if !defined(__linux__)
  +#if !defined(__linux__) || !defined(IPV6_TRANSPARENT)
  return false;
  #else
  // The linux kernel supports IP_TRANSPARENT by following patch(starting from v2.6.28) :
  