Add back option to use system taglib, add warning at the bottom

src/config.h.in

@@ -38,7 +38,6 @@
 #cmakedefine HAVE_LIBPULSE
 #cmakedefine HAVE_SPARKLE
 #cmakedefine HAVE_CHROMAPRINT
-#cmakedefine HAVE_TAGLIB_DSFFILE
 #cmakedefine HAVE_GLOBALSHORTCUTS
 #cmakedefine USE_INSTALL_PREFIX
 
@@ -55,6 +54,10 @@
 #cmakedefine HAVE_KEYSYMDEF_H
 #cmakedefine HAVE_XF86KEYSYM_H
 
+#cmakedefine USE_SYSTEM_TAGLIB
+#cmakedefine HAVE_TAGLIB_DSFFILE
+#cmakedefine HAVE_TAGLIB_DSDIFFFILE
+
 #cmakedefine USE_BUNDLE
 
 #define USE_BUNDLE_DIR "${USE_BUNDLE_DIR}"

src/core/song.cpp

@@ -68,7 +68,9 @@
 #include "covermanager/albumcoverloader.h"
 #include "tagreadermessages.pb.h"
 
+#ifndef USE_SYSTEM_TAGLIB
 using namespace Strawberry_TagLib;
+#endif
 
 const QStringList Song::kColumns = QStringList() << "title"
                                                  << "album"