nfs-utils: add patches to allow compilation against libtirpc

libtirpc does not implement the reentrant function getrpcbynumber_r(),
so allow nfs-utils to use the non-reentrant version
getrpcbynumber(). This should not be a problem as nfs-utils tools are
not multi-threaded.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>