use using declarations (#1139)

Signed-off-by: Rosen Penev <rosenp@gmail.com>

taglib/xm/xmfile.cpp

@@ -154,8 +154,7 @@ private:
 class ByteReader : public ValueReader<unsigned char>
 {
 public:
-  ByteReader(unsigned char &byte) : ValueReader<unsigned char>(byte) {}
-
+  using ValueReader::ValueReader;
   unsigned int read(TagLib::File &file, unsigned int limit) override
   {
     ByteVector data = file.readBlock(std::min(1U,limit));