On EL6 systems the packaged 2.63 version is missing AS_VAR_COPY.
This seems to have been added in 2.63b, released sometime in 2008.

With this commit we cut off any vmod development being done on
EL6 and earlier. (building and running should work)

We need pkg-config and a new libvarnishapi to build, and varnishd to run
the test suite.

The VMOD_DIR returned from pkg-config does not take prefix and similar
variables into account. Make sure to pass an explicit VMOD_DIR that
the build process has write access to.

Fixes #8

Exit with an error if we can't find libvarnishapi, instead of
just warning about missing macros.

This is useful for changing all references of libvmod-example/example
into your new vmod name.

One-off task for all vmods, but if you write more than a couple you
quickly get fed up with this drudgery.

Conflicts:
	configure.ac