+ #!+freebsd #x48000000
+ #!+openbsd #x50000000)
+ (def!constant dynamic-space-end #x88000000)
+ (def!constant alternate-signal-stack-start
+ #!+freebsd #x44000000
+ #!+openbsd #x4c000000))
+
+
+;;; don't need alternate-signal-stack-end : it's -start+SIGSTKSZ
+