CMake Error in CMakeLists.txt:
  Target "somelib" has source files which vary by configuration.  This is not
  supported by the "[^"]+" generator.

  Config "Debug":

    .*/Tests/RunCMake/target_sources/empty_1.cpp
    .*/Tests/RunCMake/target_sources/empty_2.cpp

  Config "Release":

    .*/Tests/RunCMake/target_sources/empty_1.cpp