include(CheckTypeSize) check_type_size(void* opentrack-word-size BUILTIN_TYPES_ONLY LANGUAGE C) if(NOT ((opentrack-word-size EQUAL 4) OR (opentrack-word-size EQUAL 8))) message(FATAL_ERROR "word size '${opentrack-word-size}' either misdetected or really not 4 or 8") endif() set(opentrack-word-size ${opentrack-word-size}) if(opentrack-word-size GREATER 4) set(opentrack-64bit TRUE) else() set(opentrack-64bit FALSE) endif()