For a project I'm working on, I need a crossplatform XML inspector.
GDOME2 is out because it doesn't work on OS X, so we're instead
looking at Sablotron. Looking at the Autoconf Archive I don't see
any m4 macros for Sablotron, nor does it come with a pkg-config file.
What is the canonical way to test for the existence of libsablot with
autoconf 2.60?