[master] 69976ebfa Assert

[Dridi Boukelmoune]

commit 69976ebfa0e32abc1ff430d0debcc999bcdd27e4
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Fri May 17 13:37:42 2019 +0200

    Assert

diff --git a/lib/libvarnishapi/vut.c b/lib/libvarnishapi/vut.c
index bb46128a9..0fdce6634 100644
--- a/lib/libvarnishapi/vut.c
+++ b/lib/libvarnishapi/vut.c
@@ -157,6 +157,9 @@ VUT_Arg(struct VUT *vut, int opt, const char *arg)
 	int i;
 	char *p;
 
+	CHECK_OBJ_NOTNULL(vut, VUT_MAGIC);
+	AN(opt);
+
 	switch (opt) {
 	case 'd':
 		/* Head */