tree 1f56daddb56b0e5022e9f20a9b305cfe73e132d0
parent 35bf9ded3b116209ca864eff2da481c22117e17d
author Brad King <brad.king@kitware.com> 1550586175 -0500
committer Brad King <brad.king@kitware.com> 1550586710 -0500

VS: Tell VS 2019 to use Windows SDK 8.1 explicitly when needed

VS 2019 does not default to the 8.1 SDK as VS 2017 and VS 2015 did.
When `CMAKE_SYSTEM_VERSION` is 8.1 or lower, select the 8.1 SDK
explicitly.

Fixes: #18927