CMake Error at .*Modules/WriteCompilerDetectionHeader.cmake:[0-9]+ \(message\):
  If OUTPUT_DIR is specified, then OUTPUT_FILES_VAR must also be specified.
Call Stack \(most recent call first\):
  MultiNoOutFileVar.cmake:4 \(write_compiler_detection_header\)
  CMakeLists.txt:3 \(include\)