Merge topic 'drop-osx10.6'

f2e249c0 Drop support of OS X 10.6.x; remove workarounds for it

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: David Gobbi <david.gobbi@gmail.com>
Acked-by: Michael Jackson <mike.jackson@bluequartz.net>
Acked-by: Marcus D. Hanwell <marcus.hanwell@kitware.com>
Reviewed-by: David Gobbi <david.gobbi@gmail.com>
Acked-by: Ben Boeckel <ben.boeckel@kitware.com>
Merge-request: !1798