1 files changed, 5 insertions, 0 deletions

diff --git a/rcfile_l.l b/rcfile_l.l
index c7e49fea..996197d1 100644
--- a/rcfile_l.l
+++ b/rcfile_l.l
@@ -1,3 +1,8 @@
+%top{
+/* make fileno() known */
+#define _XOPEN_SOURCE 600
+}
+
 %{
 
 /*