* login should set some environment variables now
* init should start terminals as login shells, so --single doesn't really
mean "single user" any more, just sorta single terminal session
* system() should work now since esh now accepts -c; not that vim is
still going to be unhappy because it does crazy shit.
Also, sleep() as a function (implemented by way of nanosleep) and new
absolute and relative sleep system calls added to newlib.
[ci skip] I damn well know this is going to break CI.
