[PATCH] <sys/platform/x86.h>: Remove the C preprocessor magic

[Florian Weimer]

One more thing that I forgot: It should be okay to use a function for
this.  If we ever get asymmetric multi-processing with vector
instructions inside rseq regions (so that if descheduled, they use a
non-vector fallback), anything based on a global variable will not work,
either.  The feature check would have to look at per-CPU data, requiring
a different ABI anyway.

Thanks,
Florian
-- 
Red Hat GmbH, https://de.redhat.com/ , Registered seat: Grasbrunn,
Commercial register: Amtsgericht Muenchen, HRB 153243,
Managing Directors: Charles Cachera, Brian Klemm, Laurie Krebs, Michael O'Neill