the cwd is looked up inside the kernel. The native getcwd() in libc
handles this in userland if __getcwd() fails.
Obtained from: NetBSD via OpenBSD
Tested by: Chris Casey <chriss@phys.ksu.edu>, Markus Holmberg <markush@acc.umu.se>
Reviewed by: Darrell Anderson <anderson@cs.duke.edu>
PR: kern/24315