Fix 64bit specific warnings 

This pull should be discussed in a dedicated pull as it addresses a new standard header file inclusion and I can only test for Linux 32/64 bit.

I'm not sure how the availability of this header file is on other platforms. I tried to handle it by defining the used macros if the header file is not found on a system.

To successfully build it cmake have to freshly run the configure phase.
So 
```
make clean-all
cmake ../
make
```
should do it. However the warninigs addressed in this pull only appear on 64-bit systems.