FreeRTOS+TCP on Renesas RX62N

Hi! I today tried to switch from FreeTCPIP (uIP) to FreeRTOS+TCP. I have a Renesas RDK board and my own one, both using a Renesas RX62N. I found sources at: that I decided to start with. Unfortunately, it is not that easy as I hpoed. I had to make some adjustments. Additionally, file mac.h is missing, or at least I believe it does. I tried to write it of my own, but did not succeed so far. Has someone successfully used this code? Has someone the missing file mac.h, or could give me a hint? Thanks & best regards, Stephan