(2) The "copy extra file to ${PATCHDIR}" trick doesn't work well if
${PATCHDIR} doesn't exist. Also, you need to delete the patch in
pre-clean. In addition, it may give problems to people who are
trying to build this on a read-only medium.
Solve all the above problems by calling ${PATCH_CMD} ${PATCH_ARGS}
directly on the patch in ${FILESDIR}. Also, make the message a
little clearer about what's going on.
