or1k: Define PI_STATIC_AND_HIDDEN

PI_STATIC_AND_HIDDEN means that references to static functions, data
and symbols with hidden visibility do not need any run-time relocations
after the final link, with the build flags used by glibc.

OpenRISC follows this so enabled PI_STATIC_AND_HIDDEN by adding
configure.ac and generating configure.

Suggested-by: Florian Weimer <fweimer@redhat.com>