Idea: --only-make-prerequisites

[Dan Jacobson]

Idea: --only-make-prerequisites
So
$ make --only-make-prerequisites netsift
would only make myconfdir/$J.pre myconfdir/$J.cf
and stop before the second line of

netsift:myconfdir/$J.pre myconfdir/$J.cf
        cat zz > yy
        ln q r /etc

--only-make-prerequisites is for folks that want to check and get things
ready first, before the President arrives for the button pushing
ceremony.

Sure, one could edit the Makefile, if one owns it, and put "false" on
the second line, or do make -n netsift and then run most of the lines
output, but a --only-make-prerequisites would be more elegant.