It's not available on older versions of macOS.

Bug b/115344057

Change-Id: I220a26812e5d1bc1fd0bacae490a7bdbc6a7e6df
Reviewed-on: https://swiftshader-review.googlesource.com/c/22228Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>