[PATCH] test: Fix race condition in headers-*.sh

[Guillem Jover]

Hi!

On Thu, 2016-01-07 at 17:26:12 +0100, Lukas Fleischer wrote:
> When running tests in parallel (e.g. using `make -j4 check`), the header
> tests currently fail due to headers-overlay.sh and headers-system.sh
> both generating headers-gen.c simultaneously, resulting in garbled
> output. Fix this by using separate C files for the tests.
> 
> Signed-off-by: Lukas Fleischer <lfleischer at lfos.de>

Nice catch, thanks! Merged locally, and will push later today and
prepare probably a .2 release.

Regards,
Guillem