xen-tools/libs.h currently contains a shared BUILD_BUG_ON() implementation and
is used by some tools. Extend this to include ARRAY_SIZE and clean up all the
opencoding.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>