CMake Error at .*/Modules/FeatureSummary\.cmake:[0-9]+. \(message\):
  The WHAT argument of FEATURE_SUMMARY\(\) contains FOO, which is not a valid
  value\.
Call Stack \(most recent call first\):
  FeatureSummaryWhatSingleUnknown\.cmake:[0-9]+ \(feature_summary\)
  CMakeLists.txt:[0-9]+ \(include\)