[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/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