Don't try to set unknown socket options (#1172)

* Don't try to set unknown socket options

These are not avaible on FreeBSD, for example

* individualize ifdefs

* fix whitespace

clients/roscpp/src/libros/transport/transport_tcp.cpp

@@ -179,19 +179,23 @@ void TransportTCP::setKeepAlive(bool use, uint32_t idle, uint32_t interval, uint
  }
 
 /* cygwin SOL_TCP does not seem to support TCP_KEEPIDLE, TCP_KEEPINTVL, TCP_KEEPCNT */
-#if defined(SOL_TCP) && !defined(__CYGWIN__)
+#if defined(SOL_TCP) && defined(TCP_KEEPIDLE)
  val = idle;
  if (setsockopt(sock_, SOL_TCP, TCP_KEEPIDLE, &val, sizeof(val)) != 0)
  {
  ROS_DEBUG("setsockopt failed to set TCP_KEEPIDLE on socket [%d] [%s]", sock_, cached_remote_host_.c_str());
  }
+#endif
 
+#if defined(SOL_TCP) && defined(TCP_KEEPINTVL)
  val = interval;
  if (setsockopt(sock_, SOL_TCP, TCP_KEEPINTVL, &val, sizeof(val)) != 0)
  {
  ROS_DEBUG("setsockopt failed to set TCP_KEEPINTVL on socket [%d] [%s]", sock_, cached_remote_host_.c_str());
  }
+#endif
 
+#if defined(SOL_TCP) && defined(TCP_KEEPCNT)
  val = count;
  if (setsockopt(sock_, SOL_TCP, TCP_KEEPCNT, &val, sizeof(val)) != 0)
  {