... in the 21.017 open source release the internal preprocessor symbol is off by default in Visual Studio, ia32 and em64t.
It switches on automatically in the header if compilation is being done with exception support enabled. Use /EH switch, or corresponding VS project setting.
The corresponding code in include/tbb/tbb_stddef.h should be as the following (check if it is the same in your installation):
#if defined(__EXCEPTIONS) || defined(_CPPUNWIND) || defined(__SUNPRO_CC)
#ifndef __TBB_EXCEPTIONS
#define __TBB_EXCEPTIONS 1
#endif /* __TBB_EXCEPTIONS */
#endif
_CPPUNWIND is defined by the Visual C++ compiler in case the mentioned option is set.