/* To linked list of NextAndId structs (or rather structs whose start region is
* compatible to it) starting at "start", add newly allocated element of
* "n_size" and an ID that is either "id" or, if "id" is <= UINT8_MAX and >=
/* To linked list of NextAndId structs (or rather structs whose start region is
* compatible to it) starting at "start", add newly allocated element of
* "n_size" and an ID that is either "id" or, if "id" is <= UINT8_MAX and >=