sunrpc: Do not export getrpcport by default

This function looks like an NSS function, but is actually a wrapper
around pmap_getport, so it should only be exported with
--enable-obsolete-rpc.

sunrpc/getrpcport.c

@@ -66,3 +66,8 @@ getrpcport (const char *host, u_long prognum, u_long versnum, u_int proto)
     return 0;
   return pmap_getport (&addr, prognum, versnum, proto);
 }
+#ifdef SHARED
+# ifndef EXPORT_RPC_SYMBOLS
+compat_symbol (libc, getrpcport, getrpcport, GLIBC_2_0);
+# endif
+#endif