message: Move header - only include when building with sync
diff: #include "results.hpp"
  #include "schema.hpp"
  #include "thread_safe_reference.hpp"
  -#include "sync/sync_config.hpp"
  #include "util/compiler.hpp"
  #include "util/format.hpp"
  #include <realm/util/scope_exit.hpp>
  #if REALM_ENABLE_SYNC
  +#include "sync/sync_config.hpp"
  #include <realm/sync/history.hpp>
  #endif
  