[ion/simulator] Add missing includes

ion/src/simulator/shared/display.cpp

@@ -2,6 +2,7 @@
 #include "main.h"
 #include <ion/display.h>
 #include <SDL.h>
+#include <string.h>
 
 /* Drawing on an SDL texture
  * In SDL2, drawing bitmap data happens through textures, whose data lives in

ion/src/simulator/shared/events_keyboard_platform.cpp

@@ -4,6 +4,7 @@
 #include <assert.h>
 #include <ion/events.h>
 #include <SDL.h>
+#include <string.h>
 
 namespace Ion {
 namespace Events {