Protect __shared_weak_count::__get_deleter declaration with _LIBCPP_NO_RTTI. Fixes http://llvm.org/bugs/show_bug.cgi?id=12867

llvm-svn: 157049

libcxx/include/memory

@@ -3603,7 +3603,9 @@ public:
     long use_count() const _NOEXCEPT {return __shared_count::use_count();}
     __shared_weak_count* lock() _NOEXCEPT;
 
+#ifndef _LIBCPP_NO_RTTI
     virtual const void* __get_deleter(const type_info&) const _NOEXCEPT;
+#endif
 private:
     virtual void __on_zero_shared_weak() _NOEXCEPT = 0;
 };