+# rpmbuild -D "openvswitch_version 1.1.0+build123"
+# -D "kernel_name NAME-xen"
+# -D "kernel_version 2.6.32.12-0.7.1.xs5.6.100.323.170596"
+# -D "kernel_flavor xen"
+# -D "build_number --with-build-number=123"
+# -bb /usr/src/redhat/SPECS/openvswitch-xen.spec