constify more data

 text+data text+rodata    rwdata       bss filename
-     2534        2510        24         0 libc/inet/rpc/clnt_udp.o
+     2534        2534         0         0 libc/inet/rpc/clnt_udp.o
-     1904        1880        24         0 libc/inet/rpc/clnt_tcp.o
+     1904        1904         0         0 libc/inet/rpc/clnt_tcp.o
-      770         746        24         4 libc/inet/rpc/clnt_raw.o
+      770         770         0         4 libc/inet/rpc/clnt_raw.o

libc/inet/rpc/clnt_raw.c

@@ -84,7 +84,7 @@ static bool_t clntraw_freeres (CLIENT *, xdrproc_t, caddr_t);
 static bool_t clntraw_control (CLIENT *, int, char *);
 static void clntraw_destroy (CLIENT *);
 
-static struct clnt_ops client_ops =
+static const struct clnt_ops client_ops =
 {
   clntraw_call,
   clntraw_abort,

libc/inet/rpc/clnt_tcp.c

@@ -117,7 +117,7 @@ static bool_t clnttcp_freeres (CLIENT *, xdrproc_t, caddr_t);
 static bool_t clnttcp_control (CLIENT *, int, char *);
 static void clnttcp_destroy (CLIENT *);
 
-static struct clnt_ops tcp_ops =
+static const struct clnt_ops tcp_ops =
 {
   clnttcp_call,
   clnttcp_abort,

libc/inet/rpc/clnt_udp.c

@@ -98,7 +98,7 @@ static bool_t clntudp_freeres (CLIENT *, xdrproc_t, caddr_t);
 static bool_t clntudp_control (CLIENT *, int, char *);
 static void clntudp_destroy (CLIENT *);
 
-static struct clnt_ops udp_ops =
+static const struct clnt_ops udp_ops =
 {
   clntudp_call,
   clntudp_abort,