From 8b6ebc025cf2b25fdc1e8f6e6261701dc71bac74 Mon Sep 17 00:00:00 2001
From: Mikael Pettersson <mikpelinux@gmail.com>
Date: Tue, 2 Mar 2021 15:20:06 -0700
Subject: [PATCH] [PATCH] Fix Ada bootstrap failure on Cygwin since switch to
 C++11 (PR98590)

gcc/ada
	PR bootstrap/98590
	* cstreams.c: Ensure fileno_unlocked() is visible on Cygwin.
---
 gcc/ada/cstreams.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/gcc/ada/cstreams.c b/gcc/ada/cstreams.c
index 4e00ded..8072320 100644
--- a/gcc/ada/cstreams.c
+++ b/gcc/ada/cstreams.c
@@ -37,6 +37,11 @@
 #define _FILE_OFFSET_BITS 64
 /* the define above will make off_t a 64bit type on GNU/Linux */
 
+/* Tell Cygwin's <stdio.h> to expose fileno_unlocked() */
+#if defined(__CYGWIN__) && !defined(__CYGWIN32__) && !defined(_GNU_SOURCE)
+#define _GNU_SOURCE
+#endif
+
 #include <stdio.h>
 #include <sys/types.h>
 #include <sys/stat.h>
-- 
2.7.4