Android: Remove #ifdef __cplusplus checks

A C compiler would very much be unable to build this code anyway.

Source/Android/jni/AndroidCommon/IDCache.cpp

@@ -271,11 +271,9 @@ jmethodID GetBooleanSupplierGet()
 
 }  // namespace IDCache
 
-#ifdef __cplusplus
 extern "C" {
-#endif
 
-jint JNI_OnLoad(JavaVM* vm, void* reserved)
+JNIEXPORT jint JNI_OnLoad(JavaVM* vm, void* reserved)
 {
   s_java_vm = vm;
 
@@ -382,7 +380,7 @@ jint JNI_OnLoad(JavaVM* vm, void* reserved)
   return JNI_VERSION;
 }
 
-void JNI_OnUnload(JavaVM* vm, void* reserved)
+JNIEXPORT void JNI_OnUnload(JavaVM* vm, void* reserved)
 {
   JNIEnv* env;
   if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION) != JNI_OK)
@@ -400,7 +398,4 @@ void JNI_OnUnload(JavaVM* vm, void* reserved)
   env->DeleteGlobalRef(s_network_helper_class);
   env->DeleteGlobalRef(s_boolean_supplier_class);
 }
-
-#ifdef __cplusplus
 }
-#endif

Source/Android/jni/IniFile.cpp

@@ -60,9 +60,7 @@ static void Set(JNIEnv* env, jobject obj, jstring section_name, jstring key, T n
       ->Set(GetJString(env, key), new_value);
 }
 
-#ifdef __cplusplus
 extern "C" {
-#endif
 
 JNIEXPORT jboolean JNICALL Java_org_dolphinemu_dolphinemu_utils_IniFile_00024Section_exists(
     JNIEnv* env, jobject obj, jstring key)
@@ -243,7 +241,4 @@ JNIEXPORT jlong JNICALL Java_org_dolphinemu_dolphinemu_utils_IniFile_copyIniFile
 {
   return reinterpret_cast<jlong>(new IniFile(*GetIniFilePointer(env, other)));
 }
-
-#ifdef __cplusplus
 }
-#endif

Source/Android/jni/MainAndroid.cpp

@@ -196,9 +196,7 @@ static std::string GetAnalyticValue(const std::string& key)
   return stdvalue;
 }
 
-#ifdef __cplusplus
 extern "C" {
-#endif
 
 JNIEXPORT void JNICALL Java_org_dolphinemu_dolphinemu_NativeLibrary_UnPauseEmulation(JNIEnv*,
                                                                                      jclass)
@@ -703,7 +701,4 @@ Java_org_dolphinemu_dolphinemu_NativeLibrary_GetCurrentTitleDescriptionUnchecked
 
   return ToJString(env, description);
 }
-
-#ifdef __cplusplus
 }
-#endif

Source/Android/jni/NativeConfig.cpp

@@ -94,9 +94,7 @@ static void Set(jint layer, const Config::Location& location, T value)
   Config::OnConfigChanged();
 }
 
-#ifdef __cplusplus
 extern "C" {
-#endif
 
 JNIEXPORT jboolean JNICALL
 Java_org_dolphinemu_dolphinemu_features_settings_model_NativeConfig_isSettingSaveable(
@@ -210,7 +208,4 @@ JNIEXPORT void JNICALL Java_org_dolphinemu_dolphinemu_features_settings_model_Na
 {
   return Set(layer, GetLocation(env, file, section, key), value);
 }
-
-#ifdef __cplusplus
 }
-#endif