Adjust to VDP API Changes from VC#4035

Ref https://github.com/varnishcache/varnish-cache/pull/4035

src/vdfp_pipe.c

@@ -174,9 +174,10 @@ mk_dup(int oldfd, int newfd)
 }
 
 static int v_matchproto_(vdp_init_f)
-vdp_init(VRT_CTX, struct vdp_ctx *vc, void **priv, struct objcore *objcore)
+vdp_init(VRT_CTX, struct vdp_ctx *vc, void **priv,
+    struct objcore *objcore, struct req *req,
+    struct http *hd, intmax_t *cl)
 {
-	struct req *req;
 	struct vdp_state *state;
 	struct vdp_entry *vdpe;
 	struct vdp_map map_entry, *map;
@@ -188,18 +189,19 @@ vdp_init(VRT_CTX, struct vdp_ctx *vc, void **priv, struct objcore *objcore)
 	char **argv;
 
 	CHECK_OBJ_NOTNULL(vc, VDP_CTX_MAGIC);
-	req = vc->req;
-	CHECK_OBJ_NOTNULL(req, REQ_MAGIC);
-	AN(req->vcl);
 	AN(priv);
-	AZ(*priv);
 	CHECK_OBJ_ORNULL(objcore, OBJCORE_MAGIC);
+	CHECK_OBJ_ORNULL(req, REQ_MAGIC);
+	CHECK_OBJ_NOTNULL(hd, HTTP_MAGIC);
+	AN(cl);
+
+	AZ(*priv);
 
 	vdpe = VTAILQ_LAST(&vc->vdp, vdp_entry_s);
 	CHECK_OBJ_NOTNULL(vdpe, VDP_ENTRY_MAGIC);
 	AN(vdpe->vdp);
 	map_entry.vdp = vdpe->vdp;
-	map_entry.vcl = req->vcl;
+	map_entry.vcl = ctx->vcl;
 	map = VRBT_FIND(vdp_tree, &tree_h, &map_entry);
 	CHECK_OBJ_NOTNULL(map, PIPE_VDP_MAP_MAGIC);
 	CHECK_OBJ_NOTNULL(map->obj, PIPE_VDP_MAGIC);
@@ -309,7 +311,8 @@ vdp_init(VRT_CTX, struct vdp_ctx *vc, void **priv, struct objcore *objcore)
 	state->fds[STDIN_FILENO].fd = in[1];
 	state->fds[STDOUT_FILENO].fd = out[0];
 	state->fds[STDERR_FILENO].fd = err[0];
-	http_Unset(req->resp, H_Content_Length);
+	http_Unset(hd, H_Content_Length);
+	*cl = -1;
 	return (0);
 }