Add lw_thread_test

test/Jamfile

@@ -270,3 +270,5 @@ run lsp_convertible_test.cpp ;
 run lsp_convertible_test2.cpp ;
 
 run make_shared_array_tmp_test.cpp ;
+
+run lw_thread_test.cpp : : : <threading>multi ;

test/lw_thread_test.cpp

@@ -0,0 +1,36 @@
+
+// lw_thread_test.cpp
+//
+// Copyright 2018 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+
+#include <boost/detail/lightweight_thread.hpp>
+#include <boost/detail/lightweight_test.hpp>
+#include <boost/smart_ptr/detail/atomic_count.hpp>
+
+boost::detail::atomic_count count( 0 );
+
+void f()
+{
+    ++count;
+}
+
+int main()
+{
+    int const N = 4;
+    pthread_t th[ N ] = {};
+
+    for( int i = 0; i < N; ++i )
+    {
+        boost::detail::lw_thread_create( th[ i ], f );
+    }
+
+    for( int i = 0; i < N; ++i )
+    {
+        pthread_join( th[ i ], 0 );
+    }
+
+    BOOST_TEST_EQ( count, N );
+
+    return boost::report_errors();
+}