The srandom function is not available
unless _XOPEN_SOURCE is set > 500 or an equivalent
declaration is done.
Let's set it.
Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>
Add a command line option which will seed the random generator
from /dev/urandom.
This can be usefull for some particular tests in which we are
interested in having different random numbers in each run,
but we cannot provide a different random seed from command line.
Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>