[libcxx] Set _LIBCPP_ELAST for mingw.

Reviewers: K-ballo, mclow.lists, EricWF

Reviewed By: EricWF

Subscribers: jfb, jroelofs, majnemer, cfe-commits

Differential Revision: http://reviews.llvm.org/D6558

llvm-svn: 225273
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: a76dfbd4288271d3a61fe2f4307c406780ce7c49
diff --git a/src/config_elast.h b/src/config_elast.h
new file mode 100644
index 0000000..08d0103
--- /dev/null
+++ b/src/config_elast.h
@@ -0,0 +1,36 @@
+//===----------------------- config_elast.h -------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CONFIG_ELAST
+#define _LIBCPP_CONFIG_ELAST
+
+#if defined(_WIN32)
+#include <stdlib.h>
+#else
+#include <errno.h>
+#endif
+
+#if defined(ELAST)
+#define _LIBCPP_ELAST ELAST
+#elif defined(_NEWLIB_VERSION)
+#define _LIBCPP_ELAST __ELASTERROR
+#elif defined(__linux__)
+#define _LIBCPP_ELAST 4095
+#elif defined(__APPLE__)
+// No _LIBCPP_ELAST needed on Apple
+#elif defined(__sun__)
+#define _LIBCPP_ELAST ESTALE
+#elif defined(_WIN32)
+#define _LIBCPP_ELAST _sys_nerr
+#else
+// Warn here so that the person doing the libcxx port has an easier time:
+#warning This platform's ELAST hasn't been ported yet
+#endif
+
+#endif // _LIBCPP_CONFIG_ELAST
diff --git a/src/ios.cpp b/src/ios.cpp
index d879beb..90972c4 100644
--- a/src/ios.cpp
+++ b/src/ios.cpp
@@ -8,16 +8,20 @@
 //===----------------------------------------------------------------------===//
 
 #include "__config"
+
 #include "ios"
-#include "streambuf"
-#include "istream"
-#include "string"
+
+#include <stdlib.h>
+
 #include "__locale"
 #include "algorithm"
+#include "config_elast.h"
+#include "istream"
+#include "limits"
 #include "memory"
 #include "new"
-#include "limits"
-#include <stdlib.h>
+#include "streambuf"
+#include "string"
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
diff --git a/src/system_error.cpp b/src/system_error.cpp
index 9c8adc4..c032fc0 100644
--- a/src/system_error.cpp
+++ b/src/system_error.cpp
@@ -7,11 +7,14 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define _LIBCPP_BUILDING_SYSTEM_ERROR
 #include "__config"
+
+#define _LIBCPP_BUILDING_SYSTEM_ERROR
 #include "system_error"
-#include "string"
+
+#include "config_elast.h"
 #include "cstring"
+#include "string"
 
 _LIBCPP_BEGIN_NAMESPACE_STD