diff --git a/lib/krb5/krb5_locl.h b/lib/krb5/krb5_locl.h
index 3df58d678..1f9502b43 100644
--- a/lib/krb5/krb5_locl.h
+++ b/lib/krb5/krb5_locl.h
@@ -133,4 +133,8 @@ struct sockaddr_dl;
 /* should this be public? */
 #define KEYTAB_DEFAULT "FILE:/etc/krb5.keytab"
 
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
 #endif /* __KRB5_LOCL_H__ */