Index: xen-4.1.1-testing/tools/blktap/drivers/Makefile
===================================================================
--- xen-4.1.1-testing.orig/tools/blktap/drivers/Makefile
+++ xen-4.1.1-testing/tools/blktap/drivers/Makefile
@@ -6,7 +6,6 @@ QCOW_UTIL    = img2qcow qcow2raw qcow-cr
 LIBAIO_DIR   = ../../libaio/src
 MEMSHR_DIR   = ../../memshr
 
-CFLAGS   += -Werror
 CFLAGS   += -Wno-unused
 CFLAGS   += -I../lib
 CFLAGS   += $(CFLAGS_libxenctrl)
Index: xen-4.1.1-testing/Config.mk
===================================================================
--- xen-4.1.1-testing.orig/Config.mk
+++ xen-4.1.1-testing/Config.mk
@@ -14,7 +14,7 @@ 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)
 HOSTCFLAGS += -fno-strict-aliasing
 
 DISTDIR     ?= $(XEN_ROOT)/dist