diff --git a/src/output_xhtml.h b/src/output_xhtml.h
index e3f8b4ebaa..ac405cdebd 100644
--- a/src/output_xhtml.h
+++ b/src/output_xhtml.h
@@ -31,8 +31,8 @@ class Text;
 
 namespace html {
 
-class FontTag;
-class EndFontTag;
+struct FontTag;
+struct EndFontTag;
 
 /// Attributes will be escaped automatically and so should NOT
 /// be escaped before being passed to the constructor.