Add INCOMPL() macro to mark missing code.

Add INCOMPL() macro to mark missing code.

Add http_HdrIs() to check if we have a given header and if we do
if it has a given value.

Use it.

Ignore SIGPIPE since SO_NOSIGPIPE doesn't work reliably, (but set
it on accepted TCP connections anyway).

Update passing to match fetching, including a chunked encoding method.

git-svn-id: svn+ssh://projects.linpro.no/svn/varnish/trunk@159 d4fa192b-c00b-0410-8231-f00ffab90ce4