Add missing includes

Include string.h and stdio.h explicitly.

app/src/controlevent.c

@@ -1,6 +1,7 @@
 #include "controlevent.h"
 
 #include <SDL2/SDL_stdinc.h>
+#include <string.h>
 
 #include "lockutil.h"
 #include "log.h"

app/src/server.c

@@ -3,6 +3,7 @@
 #include <errno.h>
 #include <inttypes.h>
 #include <stdint.h>
+#include <stdio.h>
 #include <SDL2/SDL_assert.h>
 #include <SDL2/SDL_timer.h>
 

app/tests/test_control_event_queue.c

@@ -1,4 +1,5 @@
 #include <assert.h>
+#include <string.h>
 
 #include "controlevent.h"
 

app/tests/test_control_event_serialize.c

@@ -1,4 +1,5 @@
 #include <assert.h>
+#include <string.h>
 
 #include "controlevent.h"