The distutils.core.Extension class has a constructor argument `include_dirs`, which includes each directory with `-I`. However, it is sometimes desirable to include additional system headers using `-isystem`. Currently, this is only possible by manually constructing the compiler argument and passing it to the `extra_compile_args` argument of distutils.core.Extension.

Since `-isystem` is a commonly used compiler option, I think it would be useful to add a new argument and attribute to distutils.core.Extension called `system_include_dirs`, which would use `-isystem` instead of `-I` when building the compiler command.

Distutils is now deprecated (see PEP 632) and all tagged issues are being closed. From now until removal, only release blocking issues will be considered for distutils.

If this issue does not relate to distutils, please remove the component and reopen it. If you believe it still requires a fix, most likely the issue should be re-reported at https://github.com/pypa/setuptools