Fix building from source on Windows

build.rs

@@ -0,0 +1,6 @@
+fn main() {
+    // Fix building from source on Windows because it can't handle file links.
+    #[cfg(windows)]
+    std::fs::copy("dev/Cargo.toml", "dev-Cargo.toml")
+        .expect("Failed to copy the file `dev/Cargo.toml` to `dev-Cargo.toml`");
+}