Sync with Linux 2.4.0-test11-pre5 Provide backward compatibility tested

Sync with Linux 2.4.0-test11-pre5 Provide backward compatibility tested
    against 2.2.18pre21
As usual, since all 2.4.0-test* kernels set LINUX_VERSION_CODE to the same
    value, if you are running a 2.4.0-test kernel, you MUST be running
    2.4.0-test11-pre4 or later (although anything after 2.4.0-test11-pre1
    should work fine -- I tested with pre4/pre5). I expect 2.2.x support to
    continue to work for all recent kernels, but I tested with 2.2.18pre21
    -- we use the old intermodule symbol communication for 2.2.x kernels,
    so they should all continue to work.