Fix a printf format error.

A couple of constifications while I wait for the tests to run.

Spotted by:	DocWilco

bin/varnishd/cache.h

@@ -710,7 +710,7 @@ int VGZ_Gzip(struct vgz *, const void **, size_t *len, enum vgz_flag);
 int VGZ_Gunzip(struct vgz *, const void **, size_t *len);
 void VGZ_Destroy(struct vgz **);
 void VGZ_UpdateObj(const struct vgz*, struct object *);
-int VGZ_WrwGunzip(struct sess *, struct vgz *, void *ibuf, ssize_t ibufl,
+int VGZ_WrwGunzip(const struct sess *, struct vgz *, void *ibuf, ssize_t ibufl,
     char *obuf, ssize_t obufl, ssize_t *obufp);
 
 /* Return values */
@@ -878,7 +878,7 @@ void RES_BuildHttp(struct sess *sp);
 void RES_WriteObj(struct sess *sp);
 void RES_StreamStart(struct sess *sp);
 void RES_StreamEnd(struct sess *sp);
-void RES_StreamPoll(struct sess *sp);
+void RES_StreamPoll(const struct sess *sp);
 
 /* cache_vary.c */
 struct vsb *VRY_Create(const struct sess *sp, const struct http *hp);

bin/varnishd/cache_gzip.c

@@ -353,7 +353,7 @@ VGZ_Gzip(struct vgz *vg, const void **pptr, size_t *plen, enum vgz_flag flags)
  */
 
 int
-VGZ_WrwGunzip(struct sess *sp, struct vgz *vg, void *ibuf, ssize_t ibufl,
+VGZ_WrwGunzip(const struct sess *sp, struct vgz *vg, void *ibuf, ssize_t ibufl,
     char *obuf, ssize_t obufl, ssize_t *obufp)
 {
 	int i;

bin/varnishd/cache_panic.c

@@ -163,7 +163,7 @@ pan_object(const struct object *o)
 	vsb_printf(vsp, "    xid = %u,\n", o->xid);
 	pan_ws(o->ws_o, 4);
 	pan_http("obj", o->http, 4);
-	vsb_printf(vsp, "    len = %lu,\n", o->len);
+	vsb_printf(vsp, "    len = %jd,\n", (intmax_t)o->len);
 	vsb_printf(vsp, "    store = {\n");
 	VTAILQ_FOREACH(st, &o->store, list)
 		pan_storage(st);

bin/varnishd/cache_response.c

@@ -423,7 +423,7 @@ RES_StreamStart(struct sess *sp)
 }
 
 void
-RES_StreamPoll(struct sess *sp)
+RES_StreamPoll(const struct sess *sp)
 {
 	struct stream_ctx *sctx;
 	struct storage *st;