[openib-general] version #defines for the kernel

[Roland Dreier]

 > > But you should also cope with
 > > non-OFED (vanilla upstream) drivers, probably by testing
 > > LINUX_VERSION_CODE too I suppose.
 > 
 > Although RHEL4 shows how this can break down in the future... they
 > backport kernel stuff while leaving LINUX_VERSION_CODE set to 2.6.9.

I don't think there's any sane way to handle that.  Since a backport
might only pick part of the new interface and stick with an old API
elsewhere, you can't have a single IB version number.  And I don't
want an ever-growing mass of "#define HAVE_FEATURE_BLAH" metastasizing
in the IB headers...