Merge topic 'CheckIncludeFile-required-libs'

a61ae3fb80 CheckIncludeFiles: Honor CMAKE_REQUIRED_LIBRARIES
391a5837ee cmake_policy: Add undocumented PARENT_SCOPE option to GET
3c47ac5b25 OpenWatcom: Add workaround for lack of error on missing library

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1978