[En-Nut-Discussion] New __NUT_EMULATION__ macro

[Matthias Ringwald]

Hi

I've started to fix the nut/os unix emulation to allow for compilation  
on unix-like devices like the iPhone. So far, we have used the  
__linux__, __APPLE__, __CYGWIN__... macros to check for the unix- 
emulation. Sometimes the check would be in a cascade like: ifdef  
__avr__ , elif __arm__ , ... On an native arm device it would follow  
the __arm__ branch which is not as intented for the unix_emulation. to  
clean this up, I've replaced most of all __APPLE__, __linux__,  
__CYGWIN__ macros with a check for __NUT_EMULATION__, and sorted the  
cascade to first test for __NUT_EMULATIO__,  and added this define to  
Makefile.unix-gcc.

BTnut compiles with the updated source, I just hope I did not break  
anything else. Just tell me.. :)
I've also fixed some other glitches when using the unix target with  
the nutsetup.

Harald, could you set the __NUT_EMULATION__ define, when using the nut- 
configurator? I've never used/looked at it.

Cheers
  Matthias