Marshall Clow:  LWG Issue 2056: future_errc enums start with value 0 (invalid value for broken_promise).

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@190756 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/future b/include/future
index b249464..9c4c70d 100644
--- a/include/future
+++ b/include/future
@@ -19,10 +19,10 @@
 
 enum class future_errc
 {
-    broken_promise,
-    future_already_retrieved,
+    future_already_retrieved = 1,
     promise_already_satisfied,
-    no_state
+    no_state,
+    broken_promise
 };
 
 enum class launch
@@ -379,10 +379,10 @@
 //enum class future_errc
 _LIBCPP_DECLARE_STRONG_ENUM(future_errc)
 {
-    broken_promise,
-    future_already_retrieved,
+    future_already_retrieved = 1,
     promise_already_satisfied,
-    no_state
+    no_state,
+    broken_promise
 };
 _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(future_errc)