[master] 3ac9ecb Only allow UDS backends in syntax >= 4.1

[Poul-Henning Kamp]

commit 3ac9ecb76e6985ef031336b6f8a162bca91fef41
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Wed Mar 14 10:55:22 2018 +0000

    Only allow UDS backends in syntax >= 4.1

diff --git a/lib/libvcc/vcc_backend.c b/lib/libvcc/vcc_backend.c
index 640481d..3f21cdb 100644
--- a/lib/libvcc/vcc_backend.c
+++ b/lib/libvcc/vcc_backend.c
@@ -365,6 +365,15 @@ vcc_ParseHostDef(struct vcc *tl, const struct token *t_be, const char *vgcname)
 			vcc_NextToken(tl);
 			SkipToken(tl, ';');
 		} else if (vcc_IdIs(t_field, "path")) {
+			if (tl->syntax < VCL_41) {
+				VSB_printf(tl->sb,
+				    "Unix socket backends only supported"
+				    " in VCL4.1 and higher.\n");
+				vcc_ErrToken(tl, tl->t);
+				VSB_printf(tl->sb, " at ");
+				vcc_ErrWhere(tl, tl->t);
+				return;
+			}
 			vcc_Redef(tl, "Address", &t_did, t_field);
 			ERRCHK(tl);
 			ExpectErr(tl, CSTR);