Expose the Android system version to the app. Useful to enable/disable android-only features like immersive mode

android/app-android.cpp

@@ -53,6 +53,7 @@ static float hat_joystick_y_async;
 
 int optimalFramesPerBuffer = 0;
 int optimalSampleRate = 0;
+static int androidVersion;
 
 // Android implementation of callbacks to the Java part of the app
 void SystemToast(const char *text) {
@@ -103,6 +104,15 @@ std::string System_GetProperty(SystemProperty prop) {
 	}
 }
 
+int System_GetPropertyInt(SystemProperty prop) {
+	switch (prop) {
+	case SYSPROP_SYSTEMVERSION:
+		return androidVersion;
+	default:
+		return -1;
+	}
+}
+
 // Remember that all of these need initialization on init! The process
 // may be reused when restarting the game. Globals are DANGEROUS.
 
@@ -154,7 +164,7 @@ extern "C" jstring Java_com_henrikrydgard_libnative_NativeApp_queryConfig
 extern "C" void Java_com_henrikrydgard_libnative_NativeApp_init
 	(JNIEnv *env, jclass, jstring jdevicetype, jstring jlangRegion, jstring japkpath,
 		jstring jdataDir, jstring jexternalDir, jstring jlibraryDir, jstring jshortcutParam,
-		jstring jinstallID, jboolean juseNativeAudio) {
+		jstring jinstallID, jboolean juseNativeAudio, jint jAndroidVersion) {
 	jniEnvUI = env;
 
 	ILOG("NativeApp.init() -- begin");
@@ -162,6 +172,7 @@ extern "C" void Java_com_henrikrydgard_libnative_NativeApp_init
 	memset(&input_state, 0, sizeof(input_state));
 	renderer_inited = false;
 	first_lost = true;
+	androidVersion = jAndroidVersion;
 
 	g_buttonTracker.Reset();