technique) so that we don't wind up calling into an application's
version if the application defines them.
Inspired by: qpopper's interfering and buggy version of strlcpy
It's silly to call sysctl() to get the value of _PATH_STDPATH from
<paths.h> when we can just use it directly. This greatly simplifies
the implementation. (This is also part of my grand scheme to get
rid of sysctl's `user' category, which should never have been created.)
Use strlcpy() instead of strncpy() as it has the exact semantics we want.
