pwd vs permissions

[utzoo!henry]

There are several setuid programs, notably uux, which invoke pwd and
expect to get coherent results.  This doesn't work too well if the
current directory, or a parent, is off-limits to anyone but the owner.
There are two possible fixes.  One is to run down such programs and
fiddle them in some manner to reset the uid before invoking pwd (this
is awkward when pwd is being invoked using system()).  The alternative,
which I've done here, is to simply make pwd setuid-root.