Fix crash on collection rescan

Closes: https://mirror.git.trinitydesktop.org/gitea/TDE/amarok/issues/87
Signed-off-by: Fat-Zer <fatzer2@gmail.com>

amarok/src/playlist.cpp

@@ -921,12 +921,15 @@ Playlist::updateEntriesStatusAdded( const TQMap<TQString,TQString> &map )
     TQMap<TQString,TQPtrList<PlaylistItem>*> uniquecopy( m_uniqueMap );
 
     TQMap<TQString,TQPtrList<PlaylistItem>*>::Iterator it;
-    for( it = uniquecopy.begin(); it != uniquecopy.end(); ++it )
+    for( it = uniquecopy.begin(); it != uniquecopy.end(); )
     {
-        if( map.contains( it.key()  ))
+        // remove() may invalidate the iterator, so make a copy and increment
+        // it before modifying the collection
+        TQMap<TQString,TQPtrList<PlaylistItem>*>::Iterator cur = it++;
+        if( map.contains( cur.key() ))
         {
-            updateEntriesStatusAdded( map[it.key()], it.key() );
-            uniquecopy.remove( it );
+            updateEntriesStatusAdded( map[cur.key()], cur.key() );
+            uniquecopy.remove( cur );
         }
     }