== A Solaris 8 _make_ bug

 ; cat Makefile
 foo : /tmp/bar
 	touch foo
 ; mkdir /tmp/bar
 ; make
 touch foo
 ; make
 `foo' is up to date.
 ; touch /tmp/bar/t
 ; make
 `foo' is up to date.
 ; gmake
 touch foo

As '_make -ndd_' shows, for some reason Solaris 8's version of make
decides that directories always have a timestamp of 0. It knows that
they exist, because if you remove _/tmp/bar_ it complains about
it. This behavior is the same for both _/usr/ccs/bin/make_ and
_/usr/xpg4/bin/make_.

On a quick test, this bug appears to be gone in Solaris 9. There's
a Solaris 8 _make_ patch not applied to our systems, but the README
doesn't mention anything like this bug.

(Depending on a directory is the kind of thing you do if you're
building something from a bunch of files dropped into a directory,
and you need to do something every time a file is added or removed.)

I note in passing that _make_ problems that cause things to not get
rebuilt are much more annoying than _make_ problems that cause things
to get rebuilt all the time.