From 25df677de39c5a922e04606f213d4c3a246bb347 Mon Sep 17 00:00:00 2001
From: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
Date: Tue, 9 Jul 2024 18:07:10 -0400
Subject: [PATCH] Add feature test macro for fileno()

Defining _XOPEN_SOURCE is required for POSIX fileno() to become
available.

Signed-off-by: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
---
 opal/util/keyval/keyval_lex.l | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/opal/util/keyval/keyval_lex.l b/opal/util/keyval/keyval_lex.l
index e0cb6ec120d..4d3697cfe3f 100644
--- a/opal/util/keyval/keyval_lex.l
+++ b/opal/util/keyval/keyval_lex.l
@@ -23,6 +23,9 @@
  * $HEADER$
  */
 
+// needed for fileno()
+#define _XOPEN_SOURCE
+
 #include "opal_config.h"
 
 #include <stdio.h>