ref: f0ea8a3f6019b4fe7d37f33b0a5a3a88fd1fcdc7
dir: /sys/src/9/boot/boot.h/
enum {
Debug = 0,
};
extern char* bootdisk;
extern void fatal(char*);
extern int readfile(char*, char*, int);
extern void run(char*, ...);
extern void setenv(char*, char*, int);
extern int writefile(char*, char*, int);