[PATCH V4] configure.ac: Fallback to older detection code if pkg-config can't find expat

[Andrew Oakley]

On 03/02/15 22:26, Bill Spitzak wrote:
> This paritally reverts commit a4afd90f9f0c27ed5f3f313b915c260673f8be34.
> 
> On older expat versions (ie the one on Ubuntu 12.04) there is no pkg-config
> file, so fall back to a test for the header and library. In addition the
> source for expat does not seem to be in a git repository but in cvs instead
> and it seems preferrable to not require cvs to build wayland.
> 
> The restored test has been updated to use AC_SEARCH_LIBS. This version
> uses empty square brackets for the unused branches, similar to many other
> if statements in configure.ac.

This seems fine to me and it seems to generate the right stuff in the
configure script.  It certainly seems better than what was there before,
but I'm not an autoconf guru.

Apologies for poking the bear, thanks for trying to fix it properly!

What I was trying to do was compile expat and wayland-scanner for host
with a non-standard prefix, then cross-compile wayland itself using the
tools we just built.  We could have passed extra configure options, but
the pkg-config solution "just works" for the majority of packages.  I
didn't think changing this would cause any trouble as expat has been
distributing pc files for many years.

Reviewed-by: Andrew Oakley <aoakley at espial.com>