Please note that the only correct template for size_t in printf is %zu.
If you try to use %d, it will fail in a x64 build. If you try to use %lld, it will fail in a x86/Win32 build.
So always use %zu for size_t parameters!
Replace here (jsonval.cpp):
s.Printf( _T("Object: Type=%s Size=%d comments=<<<USE %zu INSTEAD OF %d>>>\n"),
wxJSONValue::TypeToString( data->m_type ).c_str(),
Size(), data->m_comments.GetCount() );
and in other calls of printf with size_t parameters.
Here data->m_comments.GetCount() has size_t type.
Thanks.