LibC: Add errno for unknown error

libc/include/errno.h

@@ -91,6 +91,8 @@ __BEGIN_DECLS
 #define ENOTBLK			82
 #define EEXISTS			83
 
+#define EUNKNOWN		0xFF
+
 #define errno __errno
 
 extern int __errno;

libc/include/sys/banan-os.h

@@ -11,6 +11,9 @@ __BEGIN_DECLS
 #define TTY_FLAG_ENABLE_OUTPUT	1
 #define TTY_FLAG_ENABLE_INPUT	2
 
+#define POWER_SHUTDOWN 0
+#define POWER_REBOOT 1
+
 /*
 fildes:		refers to valid tty device
 command:	one of TTY_CMD_* definitions