Ifdef numberofHeaders out if not compiling music

This variable is only used when compiling music. Since it doesn't
actually keep track of the number of headers otherwise, ifdef it behind
VVV_COMPILEMUSIC.

desktop_version/src/BinaryBlob.cpp

@@ -12,7 +12,9 @@
 
 binaryBlob::binaryBlob(void)
 {
+#ifdef VVV_COMPILEMUSIC
     numberofHeaders = 0;
+#endif
     SDL_zeroa(m_headers);
     SDL_zeroa(m_memblocks);
 }