Import new version of libc++ into vendor branch.vendor/libc++/r152501

Approved by:	dim (mentor)

1 files changed, 7 insertions, 8 deletions

diff --git a/include/ios b/include/ios
index 7ea63a31ca71..51d50870b607 100644
--- a/include/ios
+++ b/include/ios
@@ -373,21 +373,19 @@ private:
 };
 
 //enum class io_errc
-struct _LIBCPP_VISIBLE io_errc
+_LIBCPP_DECLARE_STRONG_ENUM(io_errc)
 {
-enum _ {
     stream = 1
 };
-    _ __v_;
-
-    _LIBCPP_ALWAYS_INLINE io_errc(_ __v) : __v_(__v) {}
-    _LIBCPP_ALWAYS_INLINE operator int() const {return __v_;}
-};
+_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(io_errc)
 
 template <>
 struct _LIBCPP_VISIBLE is_error_code_enum<io_errc> : public true_type { };
+
+#ifdef _LIBCPP_HAS_NO_STRONG_ENUMS
 template <>
 struct _LIBCPP_VISIBLE is_error_code_enum<io_errc::_> : public true_type { };
+#endif
 
 _LIBCPP_VISIBLE
 const error_category& iostream_category();
@@ -574,7 +572,8 @@ public:
     typedef typename traits_type::pos_type pos_type;
     typedef typename traits_type::off_type off_type;
 
-    _LIBCPP_ALWAYS_INLINE // explicit
+    _LIBCPP_ALWAYS_INLINE
+        _LIBCPP_EXPLICIT
         operator bool() const {return !fail();}
     _LIBCPP_ALWAYS_INLINE bool operator!() const    {return  fail();}
     _LIBCPP_ALWAYS_INLINE iostate rdstate() const   {return ios_base::rdstate();}