BSP confdefs.h requirements

[Nick Withers]

Hi y'all,

https://git.rtems.org/rtems/commit/?id=bb291a4a87d3b3212999eddfa6f3b4cd
5eea4032

...I still hate that this is a thing (see 
https://lists.rtems.org/pipermail/users/2013-August/026957.html ).

Is there anything I can do or help I can lend to making this better?
-- 
Nick Withers

Embedded Systems Programmer
Department of Nuclear Physics, Research School of Physics and Engineering
The Australian National University (CRICOS: 00120C)