CMake Error in CMakeLists\.txt:
  In target "foo1" the file

    .+/Tests/RunCMake/target_sources/lib2\.c

  already belongs to file set "s[12]"\.


CMake Error in CMakeLists\.txt:
  In target "foo2" the file

    .+/Tests/RunCMake/target_sources/lib2\.c

  already belongs to file set "s1"\.
