diff --git a/conf/confbase.Y b/conf/confbase.Y
index aa46e51d..f498412a 100644
--- a/conf/confbase.Y
+++ b/conf/confbase.Y
@@ -36,6 +36,7 @@ CF_DECLS
 
 %type <i> expr bool pxlen
 
+%left '='
 %left '+' '-'
 %left '*' '/' '%'