T: check consistency of T_messages.txt with VCD functions and variables traces

Since VCD has now to go through the T tracer, we enforce the consistency
of data found in common/utils/LOG/vcd_signal_dumper.[ch] with data
found in common/utils/T/T_messages.txt.

We might get completely rid of common/utils/LOG/vcd_signal_dumper.[ch] at some
point. For the moment, let's keep it.

This commit adds the program common/utils/T/check_vcd.c and necessary
modifications to enforce its use at compilation time.

If you modify common/utils/LOG/vcd_signal_dumper.[ch] but do not update
common/utils/T/T_messages.txt an error will pop up when you compile the
software. You have to keep both modules synchronized.

common/utils/itti/intertask_interface.c

@@ -745,7 +745,7 @@ void itti_exit_task(void)
 
 #if defined(OAI_EMU) || defined(RTAI)
   if (task_id > TASK_UNKNOWN) {
-    VCD_SIGNAL_DUMPER_DUMP_VARIABLE_BY_NAME(VCD_SIGNAL_DUMPER_VARIABLE_ITTI_RECV_MSG,
+    VCD_SIGNAL_DUMPER_DUMP_VARIABLE_BY_NAME(VCD_SIGNAL_DUMPER_VARIABLES_ITTI_RECV_MSG,
                                             __sync_and_and_fetch (&itti_desc.vcd_receive_msg, ~(1L << task_id)));
   }
 #endif