message: include 0104 if PROTO_VERSION is undefined
diff: @@ -33,7 +33,7 @@ uint64_t getTime();
  // The PROTOCOL_VERSION definition is defined by the build system.
  #if !defined(PROTOCOL_VERSION)
  - #error "PROTOCOL_VERSION not defined"
  + #include "structs/0104.hpp"
  #elif PROTOCOL_VERSION == 728
  #include "structs/0728.hpp"
  #elif PROTOCOL_VERSION == 104
  