future (packaged_task(allocator_arg_t, const A&, F&&): Remove explicit (LWG 2407).

	* include/std/future (packaged_task(allocator_arg_t, const A&, F&&):
	Remove explicit (LWG 2407).

From-SVN: r223161

libstdc++-v3/ChangeLog

 2015-05-13  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/std/future (packaged_task(allocator_arg_t, const A&, F&&):
+	Remove explicit (LWG 2407).
+
 	* include/bits/basic_string.h (basic_string::basic_string()): Make
 	noexcept conditional on allocator (LWG 2455).
 

libstdc++-v3/include/std/future

@@ -1489,9 +1489,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 2097.  packaged_task constructors should be constrained
+      // 2407. [this constructor should not be] explicit
       template<typename _Fn, typename _Alloc, typename = typename
 	       __constrain_pkgdtask<packaged_task, _Fn>::__type>
-	explicit
 	packaged_task(allocator_arg_t, const _Alloc& __a, _Fn&& __fn)
 	: _M_state(__create_task_state<_Res(_ArgTypes...)>(
 		    std::forward<_Fn>(__fn), __a))