RIOT-OS/RIOT — pull request #943 by Kijewski (2014-03-29 18:14:44+00:00)
Title: Clean up test_irq

`test_irq` is messy in multiple ways:
- `busy`, `i`, and `k` need to be volatile
- `return` is missing
- `printf` is used needlessly
- `USEMODULE += posix` is used needlessly
- `return` is missing