Well, and non-unix probably don't have 'make' in the first place (does Mac have make in the global path?). But they very well might have a compiler installed in some place that Perl toolchain knows how to find, according to some magic environment variables or something, or hard-coded paths that were stored in %Config when perl was built.

This is why I was asking, instead of just stumbling forward with the idea.

I almost care more whether a system is *intended* to support XS modules than whether it can be made to compile them. If the user intends to install XS then I want to try compiling and show the message to them if it fails, rather than skipping the XS support.