+extern void protect_control_stack_guard_page(int protect_p);
+extern void protect_control_stack_return_guard_page(int protect_p);
+extern void protect_control_stack_guard_page_thread(int protect_p, struct thread *th);
+extern void protect_control_stack_return_guard_page_thread(int protect_p, struct thread* th);
+extern os_vm_address_t undefined_alien_address;
+#endif
+
+/* note for anyone trying to port an architecture's support files
+ * from CMU CL to SBCL:
+ *
+ * CMU CL had architecture-dependent header files included here to
+ * define memory map data:
+ * #ifdef LISP_FEATURE_X86
+ * #include "x86-validate.h"
+ * #endif
+ * and so forth. In SBCL, the memory map data are defined at the Lisp
+ * level (compiler/target/parms.lisp) and stuffed into the sbcl.h file
+ * created by GENESIS, so there's no longer a need for an
+ * architecture-dependent header file of memory map data.
+ */