ref: ad9b1234c365919fa9d8cdb3008b4d42acf37c60
dir: /sys/src/games/music/jukefs/catset.h/
void catsetrealloc(Catset*, int); void catsetinit(Catset*, int); void catsetfree(Catset*t); void catsetcopy(Catset*, Catset*); void catsetset(Catset*, int); int catsetisset(Catset*); void catsetorset(Catset*, Catset*); int catseteq(Catset*, Catset*);