Index: xen-unstable/Config.mk
===================================================================
--- xen-unstable.orig/Config.mk
+++ xen-unstable/Config.mk
@@ -18,7 +18,7 @@ SHELL     ?= /bin/sh
 
 # Tools to run on system hosting the build
 HOSTCC     = gcc
-HOSTCFLAGS = -Wall -Werror -Wstrict-prototypes -O2 -fomit-frame-pointer
+HOSTCFLAGS:= -Wall -Werror -Wstrict-prototypes $(RPM_OPT_FLAGS)
 
 DISTDIR     ?= $(XEN_ROOT)/dist
 DESTDIR     ?= /