rbutil: Always use Qt Multimedia to play TTS preview.

We're using it on Windows and macOS, there's no reason to not do so on
Linux.

Change-Id: I6e4d9006eff22fd4bf6b882407a5497b2f8cdd2f

rbutil/rbutilqt/configure.cpp

@@ -20,9 +20,7 @@
 #include <QProgressDialog>
 #include <QFileDialog>
 #include <QUrl>
-#if !defined(Q_OS_LINUX)
 #include <QSound>
-#endif
 
 #include "version.h"
 #include "configure.h"
@@ -951,16 +949,7 @@ void Config::testTts()
     }
     tts->stop();
     if(!filename.isEmpty()) {
-#if defined(Q_OS_LINUX)
-        QString exe = Utils::findExecutable("aplay");
-        if(exe == "") exe = Utils::findExecutable("play");
-        if(exe != "")
-        {
-            QProcess::execute(exe+" "+filename);
-        }
-#else
         QSound::play(filename);
-#endif
     }
     ui.testTTS->setEnabled(true);
     delete tts; /* Config objects are never deleted (in fact, they are

rbutil/rbutilqt/rbutilqt.pro

@@ -157,13 +157,7 @@ QT += network
 
 contains(QT_MAJOR_VERSION, 5) {
     message("Qt5 found")
-    QT += widgets
-    win32 {
-        QT += multimedia
-    }
-    macx {
-        QT += multimedia
-    }
+    QT += widgets multimedia
 }
 
 CONFIG += c++11