libc/eglibc: enable rpc in eglibc-2.16+

While eglibc-2.16 recommends to use TI-RPC instead of the old sunrpc, the
old one can be included using a configure option. Since the user can still
use TI-RPC to override the libc implementation, we enable rpc unconditionally.

Signed-off-by: Johannes Stezenbach <js@sig21.net>
Message-Id: <20121102140404.GA7707@sig21.net>
Patchwork-Id: 196564

 # Compute sparc-specific values

 CT_DoArchTupleValues() {

     # That's the only thing to override

     if [ "${CT_ARCH_64}" = "y" ]; then

         CT_TARGET_ARCH="${CT_ARCH}64"

     fi

 }