PATCH: Fix VMI and COMPAT_VDSO for 2.6.21

VMI is broken under COMPAT_VDSO, as Xen and other non hardware assisted 
hypervisors will be.  I have been working on a fix for this which works 
for older glibcs that panic when the new relocatable VDSO is used.  
However, I believe at this time that the fix is going to be too radical 
to consider at this stage in the release of 2.6.21.  We don't expect 
this config option to be turned on by vendors for new distributions, so 
at this point we are willing to drop support for it when VMI is compiled 
in, and work on a patch for 2.6.22 which more fully addresses the problem.

Please apply, thanks.

Zach