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

 reporter_name="Remy Bohmer"

 reporter_url="linux@bohmer.net"

 reporter_comment="Example for building a toolchain for m68000 bare metal targets"