Implement getrusage.
These fields of struct rusage are not supported and always set to zero at this time
long ru_nswap; /* swaps */
long ru_inblock; /* block input operations */
long ru_oublock; /* block output operations */
long ru_msgsnd; /* messages sent */
long ru_msgrcv; /* messages received */
long ru_nvcsw; /* voluntary context switches */
long ru_nivcsw; /* involuntary context switches */
test75.c is the unit test for this new function
Change-Id: I3f1eb69de1fce90d087d76773b09021fc6106539
