Merge topic 'cmstrcat-any-rvalue-arg'

1cca051470 cmStrCat(): allow any argument to be an rvalue string

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Acked-by: Ben Boeckel <ben.boeckel@kitware.com>
Merge-request: !7993