User interface > Translation options > Target options > Compiler
At the target options you can chose the kind of c++-compiler, for which the output shall be produced.
C++Builder
C++Builder is made on top of a Delphi-Compiler and has some C++ extensions to cope with language features of Delphi, which cannot be reproduced adequately with the standard C++.
Visual C++/gcc/Other
At the moment there is nearly no difference in the options to produce code for Visual C++, gcc or any other compiler. Only threadvars are treated differently for gcc. In future there might be more compiler specific conversions.
If the generated C++ code shall be used with other compilers than the C++Builder, properties are eliminated and the __fastcall directives are left out. You can change the prefixes of the names for the functions which are created instead of the properties.
Delphi2CB only supports C++Builder