Qt: Add cache dir call, for later expansion

src/platform/qt/ApplicationUpdater.cpp

@@ -136,7 +136,7 @@ QUrl ApplicationUpdater::parseManifest(const QByteArray& manifest) {
 
 QString ApplicationUpdater::destination() const {
 	QFileInfo path(updateInfo().url.path());
-	QDir dir(ConfigController::configDir());
+	QDir dir(ConfigController::cacheDir());
 	// QFileInfo::completeSuffix will eat all .'s in the filename...including
 	// ones in the version string, turning mGBA-1.0.0-win32.7z into
 	// 0.0-win32.7z instead of the intended .7z

src/platform/qt/ConfigController.cpp

@@ -382,3 +382,7 @@ const QString& ConfigController::configDir() {
 	}
 	return s_configDir;
 }
+
+const QString& ConfigController::cacheDir() {
+	return configDir();
+}

src/platform/qt/ConfigController.h

@@ -105,6 +105,7 @@ public:
 	void usage(const char* arg0) const;
 
 	static const QString& configDir();
+	static const QString& cacheDir();
 	static bool isPortable();
 
 public slots:

src/platform/qt/ForwarderController.cpp

@@ -78,7 +78,7 @@ void ForwarderController::gotManifest(QNetworkReply* reply) {
 void ForwarderController::downloadBuild(const QUrl& url) {
 	QString extension(QFileInfo(url.path()).suffix());
 	// TODO: cache this
-	QString configDir(ConfigController::configDir());
+	QString configDir(ConfigController::cacheDir());
 	m_sourceFile.setFileName(QString("%1/%2-%3-%4.%5").arg(configDir)
 		.arg(projectName)
 		.arg(m_generator->systemName())