bug#9354: wishing to build, ./configure runs eternally

[Glenn Morris <rgm@gnu.org>]

> So I had my system date set for some months before real time. Very funny.
>
> And then, when I wanted to build emacs, there goes configure checking
> round and round.

I simulated this by extracting the emacs 23.3a tarfile and then doing:

find . -exec touch -t 201111111111 '{}' '+'

to set the dates of all the files a few months in the future.

Then what should be the end of ./configure prints:

 creating src/epaths.h
 make: Warning: File `/path/to/emacs-23.3/configure' has modification
    time 6.8e+06 s in the future
./config.status --recheck

and round and round it goes.

The loop is caused by configure invoking `make epaths-force'
and the rule in Makefile that says:

  config.status: ${srcdir}/configure ${srcdir}/lisp/version.el
                ./config.status --recheck

Nothing ever changes the timestamp of configure, so it always remains
newer than config.status.