diff --git a/b2/chr.c b/b2/chr.c
index d4b9fb7..70927c5 100644
--- a/b2/chr.c
+++ b/b2/chr.c
@@ -13,6 +13,7 @@
 #include <assert.h>
 
 #include "util.h"
+#include "lang.h"
 #include "param.h"
 #include "chr.h"
 
diff --git a/b2/lang.h b/b2/lang.h
index f0c966a..ba8de4c 100644
--- a/b2/lang.h
+++ b/b2/lang.h
@@ -16,4 +16,7 @@
 void parse_hierarchy(void);
 void parse_characteristics(void);
 
+void yyerrorf(const char *fmt, ...);
+void yyerror(const char *s);
+
 #endif /* !LANG_H */
diff --git a/b2/lang.y b/b2/lang.y
index 39b67a0..0d6eefc 100644
--- a/b2/lang.y
+++ b/b2/lang.y
@@ -18,6 +18,7 @@
 #include "param.h"
 #include "chr.h"
 #include "db.h"
+#include "lang.h"
 
 #include "y.tab.h"
 
diff --git a/b2/param.c b/b2/param.c
index b07f533..ef9bf89 100644
--- a/b2/param.c
+++ b/b2/param.c
@@ -12,7 +12,7 @@
 
 #include <glib.h>
 
-#include "util.h"
+#include "lang.h"
 #include "param.h"
 
 
diff --git a/b2/util.h b/b2/util.h
index 45ba2bf..1e2431b 100644
--- a/b2/util.h
+++ b/b2/util.h
@@ -26,7 +26,4 @@
 
 const char *unique(const char *s);
 
-void yyerrorf(const char *fmt, ...);
-void yyerror(const char *s);
-
 #endif /* !UTIL_H */