diff --git a/external/historical/nawk/dist/b.c b/external/historical/nawk/dist/b.c
index 974518c2f763..3364316322fc 100644
--- a/external/historical/nawk/dist/b.c
+++ b/external/historical/nawk/dist/b.c
@@ -843,7 +843,7 @@ Node *unary(Node *np)
  * to nelson beebe for the suggestion; let's see if it works everywhere.
  */
 
-#define HAS_ISBLANK
+/* #define HAS_ISBLANK */
 
 static const struct charclass {
 	const char *cc_name;