[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

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@225273 91177308-0d34-0410-b5e6-96231b3b80d8

include/__config

@@ -21,7 +21,6 @@
 
 #if !_WIN32
 #include <unistd.h>
-#include <errno.h>  // for ELAST on FreeBSD
 #endif
 
 #define _LIBCPP_VERSION 1101
@@ -643,21 +642,6 @@ template <unsigned> struct __static_assert_check {};
 #define _LIBCPP_WCTYPE_IS_MASK
 #endif
 
-#if defined(ELAST)
-#define _LIBCPP_ELAST ELAST
-#elif defined(__linux__)
-#define _LIBCPP_ELAST 4095
-#elif defined(_NEWLIB_VERSION)
-#define _LIBCPP_ELAST __ELASTERROR
-#elif defined(__APPLE__)
-// Not _LIBCPP_ELAST needed on Apple
-#elif defined(__sun__)
-#define _LIBCPP_ELAST ESTALE
-#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
-
 #ifndef _LIBCPP_TRIVIAL_PAIR_COPY_CTOR
 #  define _LIBCPP_TRIVIAL_PAIR_COPY_CTOR 1
 #endif