diff -up xen-3.4.0/tools/libxc/Makefile.werror xen-3.4.0/tools/libxc/Makefile
--- xen-3.4.0/tools/libxc/Makefile.werror	2009-08-05 13:40:32.000000000 +0200
+++ xen-3.4.0/tools/libxc/Makefile	2009-08-05 13:40:52.000000000 +0200
@@ -52,7 +52,7 @@ GUEST_SRCS-$(CONFIG_IA64)    += xc_dom_i
 
 -include $(XEN_TARGET_ARCH)/Makefile
 
-CFLAGS   += -Werror -Wmissing-prototypes
+CFLAGS   += -Wmissing-prototypes
 CFLAGS   += $(INCLUDES) -I. -I../xenstore -I../include
 
 # Needed for posix_fadvise64() in xc_linux.c