add vmod-std to the build

[Poul-Henning Kamp]

In message <BANLkTinstRcOQ6jMXCZiKyCsoEYEpD1uAQ at mail.gmail.com>, Andrea Campi w
rites:

>Also, eventually it would be nice not to require a checked out tree.

That is guaranteed not happening for the 3.x series and it is at
best very speculative for later varnish releases.

Doing it, would require us to nail down a stable API across releases
for some of the most central bits in Varnish, and that would just
be an empty illusion.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.