+ stack_t sigstack;
+#ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
+ /* Signal handlers are run on the control stack, so if it is exhausted
+ * we had better use an alternate stack for whatever signal tells us
+ * we've exhausted it */
+ sigstack.ss_sp=((void *) thread)+dynamic_values_bytes;
+ sigstack.ss_flags=0;
+ sigstack.ss_size = 32*SIGSTKSZ;
+ sigaltstack(&sigstack,0);
+#endif