[newlib-cygwin] Cygwin: document recent changes

[Ken Brown]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=4261a8f5cac478ee299f0feb3ae478dbf287427e

commit 4261a8f5cac478ee299f0feb3ae478dbf287427e
Author: Ken Brown <kbrown@cornell.edu>
Date:   Fri Jan 17 10:52:54 2020 -0500

    Cygwin: document recent changes

Diff:
---
 winsup/cygwin/release/3.1.3 | 19 ++++++++++++++++---
 winsup/doc/new-features.xml | 15 +++++++++++++++
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/winsup/cygwin/release/3.1.3 b/winsup/cygwin/release/3.1.3
index 4897411..425d8bb 100644
--- a/winsup/cygwin/release/3.1.3
+++ b/winsup/cygwin/release/3.1.3
@@ -1,5 +1,18 @@
-Bug Fixes
----------
+What changed:
+-------------
+
+- Allow symlinks to be opened with O_PATH | O_NOFOLLOW.
+
+- Allow the pathname argument to readlinkat(2) to be an empty string,
+  provided the dirfd argument refers to a symlink opened with
+  O_PATH | O_NOFOLLOW.  The readlinkat call then operates on that
+  symlink.
+
+- Support the Linux-specific AT_EMPTY_PATH flag for fchownat(2) and
+  fstatat(2).
+
+Bug Fixes:
+----------
 
 - Define CPU_SETSIZE, as on Linux.
   Addresses: https://cygwin.com/ml/cygwin/2019-12/msg00248.html
@@ -7,6 +20,6 @@ Bug Fixes
 - Fix the problem which overrides the code page setting.
   Addresses: https://www.cygwin.com/ml/cygwin/2019-12/msg00292.html
 
-- Fix a regression that prevents the root of a drive from being the
+- Fix a regression that prevented the root of a drive from being the
   Cygwin installation root.
   Addresses: https://cygwin.com/ml/cygwin/2020-01/msg00111.html
diff --git a/winsup/doc/new-features.xml b/winsup/doc/new-features.xml
index 65bdc17..967c64a 100644
--- a/winsup/doc/new-features.xml
+++ b/winsup/doc/new-features.xml
@@ -54,6 +54,21 @@ Allow times(2) to have a NULL argument, as on Linux.
 Improve /proc/cpuinfo output and align more closely with Linux.
 </para></listitem>
 
+<listitem><para>
+Allow symlinks to be opened with O_PATH | O_NOFOLLOW.
+</para></listitem>
+
+<listitem><para>
+Allow the pathname argument to readlinkat(2) to be an empty string,
+provided the dirfd argument refers to a symlink opened with O_PATH |
+O_NOFOLLOW.  The readlinkat call then operates on that symlink.
+</para></listitem>
+
+<listitem><para>
+Support the Linux-specific AT_EMPTY_PATH flag for fchownat(2) and
+fstatat(2).
+</para></listitem>
+
 </itemizedlist>
 
 </sect2>