I doubt that the full suite of tools for Borland C++ 6.0 would even run on modern Windows systems, let alone OS X. If it's just the code you want to run, try it in Xcode. Shouldn't be a problem if it's straight-up C++, with no reliance on Windows UI elements, DLL's, etc. Just set up output to the terminal, set your target as "command line interface", "C++".
If your code utilized anything outside of the standard C++ libraries, game over.