Because lots of compilers in common use, particularly from Microsoft, don't support C99 so to work around their assheadedness you have to put in compatibility w

Because lots of compilers in common use, particularly from Microsoft, don't support C99 so to work around their assheadedness you have to put in compatibility workarounds. Those workarounds behave differently from compiler-implemented bool, and the risk of errors from those inconsistencies is significantly greater than the benefit of using bool in code.