The autoconf tar test will fail for users with UID > 2^21 since the tar ustar format is specified (which do not support high UIDs).

This causes no tar to be picked up by autoconf which causes the tar-based dist-targets (e.g dist-gzip needed for make rpms),  to fail.

The attached patch changes to tar pax format.

(This is similar to what is for another reason proposed in LU-12078.