GameActivity PATCH: rename C symbols that need export

Give C symbols that need to be exported a `_C` suffix so that they can
be linked into a Rust symbol with the correct name (Since we can't
directly export from C/C++ with Rust+Cargo)

See: rust-lang/rfcs#2771

Author: rib

android-activity/game-activity-csrc/game-activity/GameActivity.cpp

@@ -538,7 +538,7 @@ static jlong initializeNativeCode_native(
   // read configuration for the first time
   readConfigurationValues(code, javaConfig);
 
-  GameActivity_onCreate(code, rawSavedState, rawSavedSize);
+  GameActivity_onCreate_C(code, rawSavedState, rawSavedSize);
 
   code->gameTextInput = GameTextInput_init(env, 0);
   GameTextInput_setEventCallback(code->gameTextInput,
@@ -1382,8 +1382,12 @@ extern "C" int GameActivity_register(JNIEnv *env) {
                                   NELEM(g_methods));
 }
 
+// XXX: This symbol is renamed with a _C suffix and then re-exported from
+// Rust because Rust/Cargo don't give us a way to directly export symbols
+// from C/C++ code: https://github.com/rust-lang/rfcs/issues/2771
+//
 extern "C" JNIEXPORT jlong JNICALL
-Java_com_google_androidgamesdk_GameActivity_initializeNativeCode(
+Java_com_google_androidgamesdk_GameActivity_initializeNativeCode_C(
     JNIEnv *env, jobject javaGameActivity, jstring internalDataDir,
     jstring obbDir, jstring externalDataDir, jobject jAssetMgr,
     jbyteArray savedState, jobject javaConfig) {

android-activity/game-activity-csrc/game-activity/GameActivity.h

@@ -322,7 +322,7 @@ typedef void GameActivity_createFunc(GameActivity* activity, void* savedState,
  * "android.app.func_name" string meta-data in your manifest to use a different
  * function.
  */
-extern GameActivity_createFunc GameActivity_onCreate;
+extern GameActivity_createFunc GameActivity_onCreate_C;
 
 /**
  * Finish the given activity.  Its finish() method will be called, causing it

android-activity/game-activity-csrc/game-activity/native_app_glue/android_native_app_glue.c

@@ -648,9 +648,13 @@ static bool onEditorAction(GameActivity* activity, int action) {
   return true;
 }
 
+// XXX: This symbol is renamed with a _C suffix and then re-exported from
+// Rust because Rust/Cargo don't give us a way to directly export symbols
+// from C/C++ code: https://github.com/rust-lang/rfcs/issues/2771
+//
 JNIEXPORT
-void GameActivity_onCreate(GameActivity* activity, void* savedState,
-                           size_t savedStateSize) {
+void GameActivity_onCreate_C(GameActivity* activity, void* savedState,
+                             size_t savedStateSize) {
   LOGV("Creating: %p", activity);
   activity->callbacks->onDestroy = onDestroy;
   activity->callbacks->onStart = onStart;