===================================================================
RCS file: /cvs/mandoc/eqn_html.c,v
retrieving revision 1.15
retrieving revision 1.19
diff -u -p -r1.15 -r1.19
--- mandoc/eqn_html.c	2017/07/05 15:03:27	1.15
+++ mandoc/eqn_html.c	2019/03/17 18:21:45	1.19
@@ -1,4 +1,4 @@
-/*	$Id: eqn_html.c,v 1.15 2017/07/05 15:03:27 schwarze Exp $ */
+/*	$Id: eqn_html.c,v 1.19 2019/03/17 18:21:45 schwarze Exp $ */
 /*
  * Copyright (c) 2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2017 Ingo Schwarze <schwarze@openbsd.org>
@@ -26,6 +26,8 @@
 #include <string.h>
 
 #include "mandoc.h"
+#include "roff.h"
+#include "eqn.h"
 #include "out.h"
 #include "html.h"
 
@@ -227,14 +229,17 @@ out:
 }
 
 void
-print_eqn(struct html *p, const struct eqn *ep)
+print_eqn(struct html *p, const struct eqn_box *bp)
 {
 	struct tag	*t;
 
+	if (bp->first == NULL)
+		return;
+
 	t = print_otag(p, TAG_MATH, "c", "eqn");
 
 	p->flags |= HTML_NONOSPACE;
-	eqn_box(p, ep->root);
+	eqn_box(p, bp);
 	p->flags &= ~HTML_NONOSPACE;
 
 	print_tagq(p, t);