Add support for running on big-endian systems

Now qtmultimedia test suite passes on powerpc.

Change-Id: I540dff93195115ad1dc5725af7293e3b8540403f
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>

src/multimedia/audio/qwavedecoder_p.h

@@ -103,7 +103,7 @@ private:
         char        id[4];
         quint32     size;
     };
-    bool peekChunk(chunk* pChunk);
+    bool peekChunk(chunk* pChunk, bool handleEndianness = true);
 
     struct RIFFHeader
     {