[libvirt] [PATCH] autogen.sh: tell user the correct make command

[Andrea Bolognani]

On Wed, 2017-07-05 at 13:06 -0500, Eric Blake wrote:
> > This doesn't catch stderr for the make invocation, and
> > FreeBSD's make doesn't support the -v flag so you'll
> > end up with a bunch of spurious output. You can use
> > 
> >   make -v 2>&1 | grep -q "GNU Make"
> 
> Yes, that is indeed important, if you like scraping help output.  But it
> may be better to test some other GNU-only functionality instead of just
> scraping output (features, not versions, is always better when it comes
> to probing for sufficient support) - the question is whether that can be
> done in an equally compact manner.

I think we're using a bunch of construct that can only be
found in GNU make, so while having a more fine-grained
capability check would future-proof us in case (Free)BSD
make decides to implement the same features down the line
it's quite possibly more trouble than it's worth.

> Is it worth cc'ing the gnulib list for thoughts on incorporating the
> notion of "this project requires GNU make" into the $buildreq handling
> of bootstrap?

That sounds good. Not sure whether we should wait until
that's implemented or merge this (fixed) patch right away
and rewrite it in terms of gnulib's make detection once
that's available, though.

-- 
Andrea Bolognani / Red Hat / Virtualization