Merge topic 'custom-target-exe-deps'

858fdd426b add_custom_command: Disallow exe-suffixed targets in DEPENDS
58ab03c031 add_custom_command: Update dependency search heuristics

Acked-by: Kitware Robot <kwrobot@kitware.com>
Tested-by: buildbot <buildbot@kitware.com>
Merge-request: !11801