xenial: fix missing stdio.h errors in minimal examples

minimal-examples/api-tests/api-test-lws_tokenize/main.c

@@ -15,6 +15,7 @@
 
 #include <libwebsockets.h>
 #include <string.h>
+#include <stdio.h>
 
 struct expected {
 	lws_tokenize_elem e;

plugins/protocol_lws_server_status.c

@@ -26,6 +26,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
+#include <stdio.h>
 
 struct lws_ss_filepath {
 	struct lws_ss_filepath *next;