Add the Linux implementation of 'extra TLS' which will allocate space
for the rseq area at the end of the TLS blocks in allocation order.
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Michael Jeanson