Add an escape hatch for disabling the resources declaration

Author: kateinoigakukun

Package.swift

@@ -52,3 +52,17 @@ let package = Package(
         ),
     ]
 )
+
+// `resources` implicitly forces the package to link `Foundation` but
+// we don't actually need it at runtime since the `resources` declaration
+// is just for teaching carton how to bundle .js files into the package.
+// For those who really want to avoid linking `Foundation` at all, you can
+// set the `JAVASCRIPTKIT_NO_FOUNDATION` environment variable to any value
+// before running `swift test` or `swift build` to skip the `resources` declaration.
+import Foundation
+
+if ProcessInfo.processInfo.environment["JAVASCRIPTKIT_NO_FOUNDATION"] != nil {
+    for target in package.targets {
+        target.resources = nil
+    }
+}