PR libstdc++/85930 fix misaligned reference

	PR libstdc++/85930
	* include/bits/shared_ptr_base.h (_Sp_make_shared_tag::_S_ti): Align
	the static variable correctly.

From-SVN: r261155

libstdc++-v3/ChangeLog

+2018-06-04  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/85930
+	* include/bits/shared_ptr_base.h (_Sp_make_shared_tag::_S_ti): Align
+	the static variable correctly.
+
 2018-05-24  Jonathan Wakely  <jwakely@redhat.com>
 
 	PR libstdc++/78870 support std::filesystem on Windows

libstdc++-v3/include/bits/shared_ptr_base.h

@@ -516,7 +516,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     static const type_info&
     _S_ti() noexcept
     {
-      static constexpr _Sp_make_shared_tag __tag;
+      static constexpr alignas(type_info) _Sp_make_shared_tag __tag;
       return reinterpret_cast<const type_info&>(__tag);
     }
 #endif