faketime: add patch to disable -Werror

faketime: add patch to disable -Werror

faketime currently doesn't build on host machines that use gcc 8.x due
to stricter checks done by gcc, and the fact that it is built with
-Werror.

As a simple stop-gap measure, this commit patches the faketime
Makefile to not use -Werror anymore.

The actual fixes for the gcc 8.x issues have been submitted upstream
at https://github.com/wolfcw/libfaketime/pull/161, but disabling
-Werror is a much smaller fix.

Also, it is worth mentioning that removing -Werror makes the existing
patch 0001-Disable-the-non-null-compare-warning-error.patch (which was
just disabling one specific warning). We nonetheless keep this patch
around as it is a backport from upstream.

Fixes:

  http://autobuild.buildroot.net/results/bd223dfa1c4baa68e427d4941bd2e9917e22da84/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>