K-ballo pointed out that I missed one of the specializations of packaged_task when I committed r241068. Thanks for the catch.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@241095 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/future b/include/future
index 25482c6..5b5afe6 100644
--- a/include/future
+++ b/include/future
@@ -2173,7 +2173,7 @@
                   >::type
               >    
         _LIBCPP_INLINE_VISIBILITY
-        explicit packaged_task(allocator_arg_t, const _Allocator& __a, _Fp&& __f)
+        packaged_task(allocator_arg_t, const _Allocator& __a, _Fp&& __f)
              : __f_(allocator_arg, __a, _VSTD::forward<_Fp>(__f)),
                __p_(allocator_arg, __a) {}
     // ~packaged_task() = default;