Don't compile the interrupts module on Windows to fix cargo test

src/interrupts.rs

@@ -1,3 +1,9 @@
+// The x86-interrupt calling convention leads to the following LLVM error
+// when compiled for a Windows target: "offset is not a multiple of 16". This
+// happens for example when running `cargo test` on Windows. To avoid this
+// problem we skip compilation of this module on Windows.
+#![cfg(not(windows))]
+
 use gdt;
 use pic8259_simple::ChainedPics;
 use spin;