add missing tls libraries

examples/scratch_client/SConscript

@@ -6,6 +6,7 @@ Import('env_cpp11')
 Import('boostlibs')
 Import('platform_libs')
 Import('polyfill_libs')
+Import('tls_libs')
 
 env = env.Clone ()
 env_cpp11 = env_cpp11.Clone ()