Fix TTS deployment on OSX

QGCInstaller.pri

@@ -23,12 +23,19 @@ installer {
         } else {
             message("Skipping GStreamer Framework")
         }
+
         # We cd to release directory so we can run macdeployqt without a path to the
         # qgroundcontrol.app file. If you specify a path to the .app file the symbolic
         # links to plugins will not be created correctly.
         QMAKE_POST_LINK += && cd $${DESTDIR} && $$dirname(QMAKE_QMAKE)/macdeployqt $${TARGET}.app -appstore-compliant -verbose=2 -qmldir=$${BASEDIR}/src
-        # macdeploy is missing some relocations once in a while. "Fix" it:
+
+        # macdeployqt does not deploy texttospeech plugin
+        QMAKE_POST_LINK += && mkdir $${TARGET}.app/Contents/PlugIns/texttospeech
+        QMAKE_POST_LINK += && cp $$[QT_INSTALL_PLUGINS]/texttospeech/libqtexttospeech_speechosx.dylib $${TARGET}.app/Contents/PlugIns/texttospeech
+
+        # macdeployqt is missing some relocations once in a while. "Fix" it:
         QMAKE_POST_LINK += && python $$BASEDIR/tools/osxrelocator.py $${TARGET}.app/Contents @rpath @executable_path/../Frameworks -r > /dev/null 2>&1
+
         # Create package
         QMAKE_POST_LINK += && hdiutil create /tmp/tmp.dmg -ov -volname "$${TARGET}-$${MAC_VERSION}" -fs HFS+ -srcfolder "$${DESTDIR}/"
         QMAKE_POST_LINK += && mkdir -p $${DESTDIR}/package