From b9ef4ca995350d1a520aba66de1d5e4209f3eb91 Mon Sep 17 00:00:00 2001
From: Ken Brown <kbrown@cornell.edu>
Date: Sat, 19 Aug 2017 17:17:27 -0400
Subject: [PATCH] Implement renameat_noreplace on recent Cygwin

* src/sysdep.c [CYGWIN]: Include cygwin/fs.h.
(renameat_noreplace) [RENAME_NOREPLACE]: Use renameat2.
(Bug#27986)
---
 src/sysdep.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/sysdep.c b/src/sysdep.c
index 12e9c83ee9..77221097db 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -42,6 +42,10 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 # include <sys/syscall.h>
 #endif
 
+#ifdef CYGWIN
+# include <cygwin/fs.h>
+#endif
+
 #if defined DARWIN_OS || defined __FreeBSD__
 # include <sys/sysctl.h>
 #endif
@@ -2685,6 +2689,8 @@ renameat_noreplace (int srcfd, char const *src, int dstfd, char const *dst)
 {
 #if defined SYS_renameat2 && defined RENAME_NOREPLACE
   return syscall (SYS_renameat2, srcfd, src, dstfd, dst, RENAME_NOREPLACE);
+#elif defined RENAME_NOREPLACE	/* Cygwin >= 2.9.0. */
+  return renameat2 (srcfd, src, dstfd, dst, RENAME_NOREPLACE);
 #elif defined RENAME_EXCL
   return renameatx_np (srcfd, src, dstfd, dst, RENAME_EXCL);
 #else
-- 
2.14.1