pkg-conf and LD* variables

[Harlan Stenn]

pkg-conf offers the following ways to get "link flags":

--libs All link flags
--libs-only-L The -L/-R stuff
--libs-only-l The -l stuff
--static Output ilbraries suitable for static linking

and then says the union of -only-L and -only-l may be smaller than the
output of -libs because the latter might include flags like -rdynamic.

We're already having to parse the output of pkg-config to try and
separate LDADD stuff from LDFLAGS stuff, And this is before we start to
address static v. dynamic things.

This is because we really don't want -L stuff in LDADD, because we end
up with things like:

No rule to make: -L /usr/local/lib

(or something).

The autoconf macro PKG_CHECK_MODULES hasn't been all that helpful to us.

What's a good way to deal with this?

One could say that pkg-conf could be doing a better job. But even if it
does, this would still require the folks who write the .pc files to do a
better job of specifying their contents.

Until we can expect .pc files to have proper content, I suspect we're
going to need to have better smarts in autoconf/automake.

But this will also require some better info about exactly how to do
this, and it MIGHT be useful to augment PKG_CHECK_MODULES.

Does anybody have some good/complete example cases for this?

What's a good way to evolve this?