xen-tools: fixed build by removing -Werror

base/xen-tools/xen-tools.conf

@@ -2,7 +2,7 @@
 # This copyright note is auto-generated by ./scripts/Create-CopyPatch.
 #
 # Filename: package/.../xen-tools/xen-tools.conf
-# Copyright (C) 2010 The OpenSDE Project
+# Copyright (C) 2010 - 2011 The OpenSDE Project
 # Copyright (C) 2004 - 2006 The T2 SDE Project
 #
 # More information can be found in the files COPYING and README.
@@ -14,3 +14,5 @@
 # --- SDE-COPYRIGHT-NOTE-END ---
 
 custmain="make xen tools; make install-xen install-tools"
+
+var_append CC_WRAPPER_REMOVE " " "-Werror"