diff --git a/src/Makefile.in b/src/Makefile.in
index 83c2d015..16bf9ac6 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -50,7 +50,7 @@ expandlabel.c expandlabel.h: expandlabel.y
 	bison -d -o expandlabel.c  expandlabel.y
 
 eval_expr.c: eval_expr.y
-	bison -o eval_expr.c eval_expr.y
+	bison -p kk -o eval_expr.c eval_expr.y
 
 parselabel.o: expandlabel.h
 
diff --git a/src/eval_expr.y b/src/eval_expr.y
index 26f8d21d..cb6a3a85 100644
--- a/src/eval_expr.y
+++ b/src/eval_expr.y
@@ -55,7 +55,7 @@ struct fn fn_array[]
     };
 %}
 
-%define api.prefix {kk}
+/* %define api.prefix {kk} */
 %union {
 int          c;
 double     val; /* For returning numbers. */