[newlib-cygwin] Cygwin: mmap: document recent bugfix

[Ken Brown]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=eeb2dc1537d2e7de509cec7b88484358d138f231

commit eeb2dc1537d2e7de509cec7b88484358d138f231
Author: Ken Brown <kbrown@cornell.edu>
Date:   Tue Jul 21 17:57:37 2020 -0400

    Cygwin: mmap: document recent bugfix

Diff:
---
 winsup/cygwin/release/3.1.7 | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/winsup/cygwin/release/3.1.7 b/winsup/cygwin/release/3.1.7
index 0c437e9e9..2f4856495 100644
--- a/winsup/cygwin/release/3.1.7
+++ b/winsup/cygwin/release/3.1.7
@@ -8,3 +8,6 @@ Bug Fixes:
 
 - Fix multiple reader support for FIFOs
   Addresses: https://sourceware.org/pipermail/cygwin/2020-July/245456.html
+
+- Fix an mmap issue that could cause failure with errno EFBIG
+  Partially addresses: https://sourceware.org/pipermail/cygwin/2020-July/245557.html