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 \(include\)