Here an update trying to port the library from this App so it is compatible with the DUE:
Ok, so the EEPROM which is not available on the DUE I fixed with commenting out everything which had to do with the "Alarm"-widget which is running on the App.
Next problem: it was using the functions "ltoa()" and "itoa()". Here I commented out everything what was using these functions. These functions are not ANSI C. I am not sure why the compiler from the UNO is able to use it, and the DUE's compiler isn't.
Next problem --> cli() and sei() functions were used. I changed this to noInterrupts() and interrupts() and the problem was gone. Is this the right thing to do?
Now I still have a final problem. I have been trying some things, but at the end I did not find a solution. The Arduino IDE gives me this message when I try to compile:
In file included from c:\program files (x86)\arduino\hardware\tools\g++_arm_none_eabi\bin\../lib/gcc/arm-none-eabi/4.4.1/../../../../arm-none-eabi/include/stdlib.h:21,
from C:\Program Files (x86)\Arduino\hardware\arduino\sam\cores\arduino/Printable.h:23,
from C:\Program Files (x86)\Arduino\hardware\arduino\sam\cores\arduino/IPAddress.h:29,
from C:\Program Files (x86)\Arduino\libraries\WiFi\src/WiFi.h:11,
c:\program files (x86)\arduino\hardware\tools\g++_arm_none_eabi\bin\../lib/gcc/arm-none-eabi/4.4.1/../../../../arm-none-eabi/include/sys/reent.h:490: error: #if with no expression
--> IOSControllerWiFi_PiR.cpp / .h is the Library they provide together with the demo sketch. It seems like it is tracking a problem down to Printable.h, or stdlib.h ,... but here I cannot change anything. I also do not see what I could change there to solve the problem. Also in the file reent.h I do not know what to do.
I have put the "almost" DUE compatible library in attachment together with the sketch i am using. Note that this is the library which works together with the WiFi shield from Arduino.
Who can help me out?