android/: Add proper C++ inclusion guards.

Change-Id: Ie3f03d967323448eda87f7b4454345323d5bfec0
diff --git a/android/main-common.h b/android/main-common.h
index 523e441..38efbd5 100644
--- a/android/main-common.h
+++ b/android/main-common.h
@@ -13,10 +13,13 @@
 #define ANDROID_MAIN_COMMON_H
 
 #include <stdint.h>
-#include "android/cmdline-option.h"
-#include "android/skin/keyset.h"
-#include "android/config-file.h"
 #include "android/avd/hw-config.h"
+#include "android/cmdline-option.h"
+#include "android/config-file.h"
+#include "android/skin/keyset.h"
+#include "android/utils/compiler.h"
+
+ANDROID_BEGIN_HEADER
 
 /* Common routines used by both android/main.c and android/main-ui.c */
 
@@ -103,4 +106,6 @@
  */
 int attach_ui_to_core( AndroidOptions* opts );
 
+ANDROID_END_HEADER
+
 #endif /* ANDROID_MAIN_COMMON_H */