Merge topic 'try_compile-platform-vars'

40f380fcb0 cmCoreTryCompile: Replace vector push_back with emplace_back
c6b0657f5b cmCoreTryCompile: Move platform variable forwarding to dedicated block

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !7243