-/*
- * what low-level signal handlers looked like before
- * undoably_install_low_level_interrupt_handler() got involved
- */
-struct low_level_signal_handler_state {
- int was_modified;
- void (*handler)(int, siginfo_t*, void*);
-} old_low_level_signal_handler_states[NSIG];
+/* SBCL used to have code to restore signal handlers on exit, which
+ * has been removed from the threaded version until we decide: exit of
+ * _what_ ? */
+
+/* SBCL comment: The "undoably" aspect is because we also arrange with
+ * atexit() for the handler to be restored to its old value. This is
+ * for tidiness: it shouldn't matter much ordinarily, but it does
+ * remove a window where e.g. memory fault signals (SIGSEGV or SIGBUS,
+ * which in ordinary operation of SBCL are sent to the generational
+ * garbage collector, then possibly onward to Lisp code) or SIGINT
+ * (which is ordinarily passed to Lisp code) could otherwise be
+ * handled bizarrely/brokenly because the Lisp code would try to deal
+ * with them using machinery (like stream output buffers) which has
+ * already been dismantled. */
+
+/* I'm not sure (a) whether this is a real concern, (b) how it helps
+ anyway */