CMake failure in application

[lifflander]

Describe the bug
Darma sync into EMPIRE failed this weekend. Here’s the output:

23:13:24  -- Configuring done
23:13:25  CMake Error: install(EXPORT "vt" ...) includes target "vt" which requires target "detector" that is not in this export set, but in multiple other export sets: cmake/checkpointTargets.cmake, cmake/detectorTargets.cmake.
23:13:25  An exported target cannot depend upon another target which is exported multiple times. Consider consolidating the exports of the "detector" target to a single export.
23:13:26  CMake Error in TPL/vt/src/CMakeLists.txt:
23:13:26    export called with target "vt" which requires target "detector" that is not
23:13:26    in this export set, but in multiple other export sets:
23:13:26    /scratch/empire-jenkins/empire-darma-updates-jobs/clang-opt-serial-static/build/TPL/checkpoint/src/checkpointTargets.cmake,
23:13:26    /scratch/empire-jenkins/empire-darma-updates-jobs/clang-opt-serial-static/build/TPL/detector/detectorTargets.cmake.
23:13:26  
23:13:26  
23:13:26    An exported target cannot depend upon another target which is exported
23:13:26    multiple times.  Consider consolidating the exports of the "detector"
23:13:26    target to a single export.
23:13:26  
23:13:26  
23:13:26  -- Generating done
23:13:26  CMake Generate step failed.  Build files cannot be regenerated correctly.