rbutil: Qt6: allow building without Multimedia module.

Qt6 beta doesn't include the Multimedia module. Allow building without,
and disable on Qt6 for now.

Change-Id: Ie2ad25c81d9c62c8c6e8efaf8309b3600afce1d0

rbutil/rbutilqt/configure.cpp

@@ -20,7 +20,9 @@
 #include <QProgressDialog>
 #include <QFileDialog>
 #include <QUrl>
+#ifdef QT_MULTIMEDIA_LIB
 #include <QSound>
+#endif
 
 #include "version.h"
 #include "configure.h"
@@ -446,7 +448,11 @@ void Config::updateTtsState(int index)
     {
         ui.configTTSstatus->setText(tr("Configuration OK"));
         ui.configTTSstatusimg->setPixmap(QPixmap(QString::fromUtf8(":/icons/go-next.png")));
+#ifdef QT_MULTIMEDIA_LIB
         ui.testTTS->setEnabled(true);
+#else
+        ui.testTTS->setEnabled(false);
+#endif
     }
     else
     {
@@ -895,6 +901,7 @@ void Config::configTts()
 
 void Config::testTts()
 {
+#ifdef QT_MULTIMEDIA_LIB
     QString errstr;
     int index = ui.comboTts->currentIndex();
     TTSBase* tts;
@@ -947,6 +954,7 @@ void Config::testTts()
     delete tts; /* Config objects are never deleted (in fact, they are
                    leaked..), so we can't rely on QObject, since that would
                    delete the TTSBase instance on application exit */
+#endif
 }
 
 void Config::configEnc()

rbutil/rbutilqt/rbutilqt.pro

@@ -157,7 +157,10 @@ TARGET = RockboxUtility
 QT += network
 
 message("Qt$$QT_MAJOR_VERSION found")
-QT += widgets multimedia
+QT += widgets
+if (lessThan(QT_MAJOR_VERSION, 6)) {
+    QT += multimedia
+}
 
 CONFIG += c++11