From 5bea45dea17c136ac8134296af12899f521beea4 Mon Sep 17 00:00:00 2001
From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Sat, 7 Jan 2017 05:13:32 +0000
Subject: [PATCH] system_error: correct ELAST emulation on Windows

ELAST should point to the last valid error string value.  However,
`_sys_nerr` provides the number of elements in the errlist array.  Since
the index is 0-based, this is off-by-one.  Adjust it accordingly.

Thanks to David Majnemer for catching this!

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291336 91177308-0d34-0410-b5e6-96231b3b80d8
---
 src/include/config_elast.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/include/config_elast.h b/src/include/config_elast.h
index 97104290d..8328978ef 100644
--- a/src/include/config_elast.h
+++ b/src/include/config_elast.h
@@ -31,7 +31,7 @@
 #elif defined(__sun__)
 #define _LIBCPP_ELAST ESTALE
 #elif defined(_LIBCPP_MSVCRT)
-#define _LIBCPP_ELAST _sys_nerr
+#define _LIBCPP_ELAST (_sys_nerr - 1)
 #else
 // Warn here so that the person doing the libcxx port has an easier time:
 #warning ELAST for this platform not yet implemented