Add more dependencies.
Add more dependencies.

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

aondio/libvmod-cowsay,Dridi/libvmod-example,aondio/libvmod-rtfrontend,varnish/libvmod-example,aondio/libvmod-cowsay,mbgrydeland/libvmod-fsbackend,Dridi/libvmod-example,varnish/libvmod-example,mbgrydeland/libvmod-fsbackend,aondio/libvmod-rtfrontend,aondio/libvmod-rtfrontend