VS: Fix Windows 10 SDK version selection (#15831)

In commit v3.4.0-rc1~5^2~1 (VS: Add support for selecting the Windows 10
SDK, 2015-09-30) we added Windows 10 SDK selection choosing the most
recent SDK that is not newer than the target version.  This is backward
because it should be up to the application code to not use APIs newer
than the target version.  It is up to the build system to provide a SDK
that has at least the APIs expected to be available for the target
version.  Furthermore, since the default target version is the host
version of Windows, the old approach breaks when the only SDK available
is for a newer version of Windows.

Fix this by always selecting a Windows 10 SDK if one exists.  Use the
SDK for the exact version if is available.  Otherwise use the latest
version of the SDK available because that will have at least the APIs
expected for the target version.
1 file changed