Fix up function declarations to fix compile errors on clang

bin/varnishd/cache_backend.h

@@ -153,9 +153,10 @@ void VBE_DropRefVcl(struct backend *);
 void VBE_DropRefLocked(struct backend *b);
 
 /* cache_backend_poll.c */
-void VBP_Insert(struct backend *b, struct vrt_backend_probe const *p, const char *hosthdr);
-void VBP_Remove(struct backend *b, struct vrt_backend_probe const *p);
-void VBP_Use(const struct backend *b, const struct vrt_backend_probe const *p);
+void VBP_Insert(struct backend *b, const struct vrt_backend_probe *p,
+    const char *hosthdr);
+void VBP_Remove(struct backend *b, const struct vrt_backend_probe *p);
+void VBP_Use(const struct backend *b, const struct vrt_backend_probe *p);
 void VBP_Summary(struct cli *cli, const struct vbp_target *vt);
 
 /* Init functions for directors */

bin/varnishd/cache_backend_poll.c

@@ -475,7 +475,8 @@ vbp_new_vcl(const struct vrt_backend_probe *p, const char *hosthdr)
  */
 
 void
-VBP_Insert(struct backend *b, const struct vrt_backend_probe *p, const char *hosthdr)
+VBP_Insert(struct backend *b, const struct vrt_backend_probe *p,
+    const char *hosthdr)
 {
 	struct vbp_target *vt;
 	struct vbp_vcl *vcl;
@@ -542,7 +543,7 @@ VBP_Use(const struct backend *b, const struct vrt_backend_probe *p)
 }
 
 void
-VBP_Remove(struct backend *b, struct vrt_backend_probe const *p)
+VBP_Remove(struct backend *b, const struct vrt_backend_probe *p)
 {
 	struct vbp_target *vt;
 	struct vbp_vcl *vcl;