ref: c7d9da8f5a41b833946027c802e0e8d7dd014b22
dir: /sys/src/cmd/postscript/p9bitpost/pslib.h/
char *psinit(int, int); /* second arg is debug flag; returns "" on success */ int image2psfile(int, Memimage*, int); void psopt(char *, void *); int paperlength; int paperwidth;