> Not, it's not! It cannot possibly be POSIX compatible if it doesn't use
> a leading slash.

Indeed.  I think POSIX merely points out that it is possible to leave
the slash out (as a purely technical realisation) and points out the
pitfalls if one does so.  I don't believe the spec should be
interpreted as meaning any more than exactly this much.

That it does not explicitly suggest that leaving the leading slash out
leads to not being compliant is merely an understandable omission.

++L