g++ ignore unrecognized command options

Question

g++ will not allow me to build a package with an unrecognized command line option

$ g++ -Wshorten-64-to-32 
g++-5: error: unrecognized command line option '-Wshorten-64-to-32'

I need g++ to allow this unrecognized command line option. Is this possible?

edit

Is this possible using homebrew g++-5?

Answer 1

I need g++ to allow this unrecognized command line option. Is this possible?

No, that option is not supported by upstream GCC. It was added by Apple to their modified GCC.

-Wconversion should give some of the same warnings.