ref: fd8a2d81c3ddf6584d2b47f1b8efe30b66beb7b5
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;