MXS-1360 Make it possible to specify thread stack size

It is now possible to specify the thread stack size to be used,
when a new thread is created. This will subsequently be used
for allowing the stack size to be specified for worker threads.

server/modules/filter/tpmfilter/tpmfilter.c

@@ -268,7 +268,7 @@ createInstance(const char *name, char **options, MXS_CONFIG_PARAMETER *params)
          * Launch a thread that checks the named pipe.
          */
         THREAD thread;
-        if (!error && thread_start(&thread, checkNamedPipe, (void*)my_instance) == NULL)
+        if (!error && thread_start(&thread, checkNamedPipe, (void*)my_instance, 0) == NULL)
         {
             MXS_ERROR("Couldn't create a thread to check the named pipe: %s", strerror(errno));
             error = true;