Move the function that pushes the compiled VCL programs C source through

Move the function that pushes the compiled VCL programs C source through
the systems cc(1) from the VCL compiler library to the varnishd process.

This reduces the VCL-compiler library to a text-procesing functionality
and makes it easier to build other tools, including test-suites,
around the VCL-compiler.

It also moves the actual compiler invocation string into the varnishd
sources, where it can be handled appropriately, possibly as a paramter.

git-svn-id: svn+ssh://projects.linpro.no/svn/varnish/trunk@1306 d4fa192b-c00b-0410-8231-f00ffab90ce4