Re: make bootstrap fails.

[Luc Teirlinck <teirllm@dms.auburn.edu>]

There would seem to be four possibilities:

1.  CDPATH=

2.  export CDPATH=

3.  use the shell command `unset CDPATH' at various places all over
    Makefile.in. 

4.  systematically do `cd ./dir' rather than `cd dir' at every single
    occurrence of cd in all Makefiles.  That includes the case where
    dir is a variable expanding to a relative name.

Clearly, 3 and 4 require both some initial work and carefulness when
subsequently making changes to the Makefile.  So I believe they should
only be considered if we agreed that both 1 and 2 are too simplistic.
Note also that, even without any change, problems only develop with a
user CDPATH _not starting with a colon_.  Personally, I would not want
to be using such a CDPATH and certainly not export it, because it
seems like a dangerous thing to do.  Richard has already stated that
he does not believe that the problem is worth a substantial amount of
work.

There are currently no instances of use of the make `export' directive
in Makefile.in.  Maybe it was avoided because some make's do not
understand it.  Hence I am afraid that (2) might break some make's
even if CDPATH is unset.  Maybe somebody can assure me that this fear
is groundless.

(1) definitely seems to work for GNU make and might work for other
makes, maybe even all makes.  Importantly, it will not make the
situation _worse_ for _any_ make.  On the other hand (3) is used at
some (but not enough) places in Makefile.in already, so maybe (1)
will not solve the problem for _all_ makes.

What if I just go ahead and install my trivial "CDPATH=" change, which
as already said, at least will do no harm and at least some good?
Then we can always decide what to do if problems persist for some non
GNU make's, say maybe clearmake.  (Maybe add `export' or maybe go for
(3).)

People with possibly problematic make's can always experiment by
making directories, say ~/cdpath and ~/cdpath/src and doing `export
CDPATH=~/cdpath" before bootstrapping or using other instances of
make.  (Of course, do not forget to set CDPATH back afterwards.)

Sincerely,

Luc.