Fix non-C99 build

src/debug/traces/starpu_fxt.c

@@ -4441,11 +4441,13 @@ void _starpu_fxt_number_events_file_close(void)
 {
 	if (number_events_file)
 	{
+		int i;
+
 		assert(number_events != NULL);
 
 		fprintf(number_events_file, "# Use starpu_fxt_number_events_to_names.py to convert event keys to event names.\n");
 
-		for (int i = 0; i <= FUT_SETUP_CODE; i++)
+		for (i = 0; i <= FUT_SETUP_CODE; i++)
 		{
 			if (number_events[i] > 0)
 				fprintf(number_events_file, "0x%x\t%lu\n", i, number_events[i]);