--- a/grammar.y
+++ b/grammar.y
@@ -73,7 +73,7 @@ static struct qual qerr = { Q_UNDEF, Q_UNDEF, Q_UNDEF, Q_UNDEF };
 int n_errors = 0;
 struct ctrl *root;
 char *yyfilename;
-int yylineno;
+extern int yylineno;
 
 #ifdef HAVE_STDARG_H
 /* GCC complains if we declare this function in traditional style */