PR68925 don't use thread_local static for stateless object

	PR libstdc++/68925
	* include/experimental/random (randint): Use temporary instead of
	thread_local static.

From-SVN: r244584

libstdc++-v3/ChangeLog

+2017-01-18  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/68925
+	* include/experimental/random (randint): Use temporary instead of
+	thread_local static.
+
 2017-01-17  Joshua Conner  <joshconner@google.com>
 
 	* crossconfig.m4: Add fuchsia OS.

libstdc++-v3/include/experimental/random

@@ -54,8 +54,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       static_assert(is_integral<_IntType>::value && sizeof(_IntType) > 1,
 		    "argument must be an integer type");
       using _Dist = std::uniform_int_distribution<_IntType>;
-      static thread_local _Dist __dist;
-      return __dist(_S_randint_engine(), typename _Dist::param_type{__a, __b});
+      // This relies on the fact our uniform_int_distribution is stateless,
+      // otherwise we'd need a static thread_local _Dist and pass it
+      // _Dist::param_type{__a, __b}.
+      return _Dist(__a, __b)(_S_randint_engine());
     }
 
   inline void