Description of problem: xdr-common.h needs to define xdr_sizeof when using libtirpc
REVIEW: https://review.gluster.org/18970 (xdr: Fix build errors due to missing xdr symbol when building against TIRPC) posted (#2) for review on master by Shreyas Siravara
https://review.gluster.org/#/c/glusterfs/+/18970/ has been merged. Hence closing this bug.