Since this is a variable only used as a temporary here, I think it's a little cleaner to introduce an anonymous scope instead of two #define blocks, that is:

```
...
beaconMsg = call BeaconSend.getPayload(&beaconMsgBuffer, call BeaconSend.maxPayloadLength());
#ifdef TOSSIM
{
    uint8_t maxLength;
    maxLength = call BeaconSend.maxPayloadLength();
    dbg("TreeRoutingCtl","TreeRouting initialized. (used payload:%d max payload:%d!\n", sizeof(beaconMsg), maxLength);
}
#endif