LaTeX OS recognition [duplicate]

This question already has an answer here:

• Is there a macro telling which OS we're using? 1 answer

Let's say I want to create a document class. Is there a way to make LaTex choose between packages (or package options) depending on the OS I'm working on?

More precisely, I want LaTeX to switch automatically between \RequirePackage[utf8]{inputenc} on Linux derivatives and \RequirePackage[latin1]{inputenc} on Windows.