diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index cf6bfc9509a2..482f64ee4604 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,9 @@
 2018-06-15  Jonathan Wakely  <jwakely@redhat.com>
 
+	PR libstdc++/86168
+	* include/bits/random.h (random_device(const string&)): Remove
+	default argument.
+
 	* include/bits/char_traits.h (__cpp_lib_constexpr_char_traits): Only
 	define for C++17 and above.
 
diff --git a/libstdc++-v3/include/bits/random.h b/libstdc++-v3/include/bits/random.h
index 738c62fccd12..e59c8b0221d0 100644
--- a/libstdc++-v3/include/bits/random.h
+++ b/libstdc++-v3/include/bits/random.h
@@ -1614,7 +1614,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     random_device() { _M_init("mt19937"); }
 
     explicit
-    random_device(const std::string& __token = "mt19937")
+    random_device(const std::string& __token)
     { _M_init_pretr1(__token); }
 #endif