Re: canonicalize: remove redundant macro definitions

[Bruno Haible]

Hello Jim,

> I'd rather defer this sort of change, since it introduces a hard
> dependency on gnulib-tool, with only marginal added value.  With this
> sort of change, a project that uses this module without going through
> gnulib-tool will not work properly.
>
> If/once we all agree that it's ok to strongly discourage (preferably
> via automated checks) the use of gnulib without gnulib-tool, then I'd
> have no objection whatsoever to this sort of change.

I've now removed the "magic" from gnulib-tool's func_get_autoconf_snippet
function, and instead created a gnulib-common.m4 that people not using
gnulib-tool can use in their project.

There are actually 3 ways to use gnulib:
  1) manual file copies, considering the contents of the module descriptions,
  2) using a script based on the elementary --extract-... accessors of
     gnulib-tool,
  3) using gnulib-tool --import.

The way it's done now harmonizes with all 3 ways to use gnulib.

Bruno