This fix avoids a WS_Alloc panic when pushing fetch processors
and should thus avoid panics by overflowing the backend workspace in vcl.

This overflow is logged as FetchError "Bo workspace overflowed".

Other panic points due to workspace_backend being set too low still exist.

Sizing estimate for workspace_backend:

	sizeof(struct busyobj)
	+ 3 * HTTP_estimate(cache_param->http_max_hdr)
	+ cache_param->vsl_buffer
	+ cache_param->http_resp_size
	+ fetch processor memory
	+ space required in VCL

Fixes #1739

As discussed on irc.  OK'd by phk@.

OK'd by phk@.

Allow to split https URI in the request line

it contribute panic dumping methods

Just warn unless --strict is used.  This allows to use the same .vcc in
4.0 and 4.1.

session number.

When building multiple vmods from the same source directory,
vmodtool would trample on other concurrent jobs' vcc_if.[ch].

Pointed out by phk@.

Using os.path.join() instead of string concatination is easier
to read.

I've verified the rest and only these 2 were affected.

Always use an oc+TRANSIENT for buffering, just don't commit the
storage if not caching.

tour through vcl_recv{}

Fixes: #1857