--- xen.orig/Rules.mk	2005-03-23 17:43:41.000000000 -0600
+++ xen/Rules.mk	2005-03-28 16:03:16.920236840 -0600
@@ -6,6 +6,7 @@ trace       ?= n
 optimize    ?= y
 domu_debug  ?= n
 crash_debug ?= n
+pae         ?= n
 
 # Currently supported architectures: x86_32, x86_64
 XEN_COMPILE_ARCH    ?= $(shell uname -m | sed -e s/i.86/x86_32/)
@@ -71,6 +72,12 @@ ifeq ($(trace),y)
 CFLAGS += -DTRACE_BUFFER
 endif
 
+ifeq ($(pae),y)
+	ifeq ($(XEN_TARGET_ARCH),x86_32)
+	CFLAGS += -DCONFIG_PAE
+	endif
+endif
+
 CFLAGS := $(strip $(CFLAGS))
 
 %.o: %.c $(HDRS) Makefile