Fix npm link usage on Node.js 6 (#815)

Author: jamestalmage

lib/fork.js

@@ -31,9 +31,35 @@ module.exports = function (file, opts) {
 		} : false
 	}, opts);
 
-	var ps = childProcess.fork(path.join(__dirname, 'test-worker.js'), [JSON.stringify(opts)], {
-		cwd: path.dirname(file),
-		silent: true,
+	// Workaround for breakage caused by https://github.com/nodejs/node/pull/5950
+	// Those changes will be reverted in https://github.com/nodejs/node/pull/6537
+
+	// Revert #815 when these changes land in Node.js
+	var execArgv = process.execArgv;
+	var cwd = path.dirname(file);
+
+	// This whole if statement is copied straight out of Nodes `child_process`
+	if (process._eval != null) { // eslint-disable-line
+		var index = execArgv.lastIndexOf(process._eval);
+		if (index > 0) {
+			// Remove the -e switch to avoid fork bombing ourselves.
+			execArgv = execArgv.slice();
+			execArgv.splice(index - 1, 2);
+		}
+	}
+
+	var testWorkerPath = path.join(__dirname, 'test-worker.js');
+
+	var args = execArgv.concat([
+		'-e',
+		'require(' + JSON.stringify(testWorkerPath) + ')',
+		testWorkerPath,
+		JSON.stringify(opts)
+	]);
+
+	var ps = childProcess.spawn(process.execPath, args, {
+		cwd: cwd,
+		stdio: ['pipe', 'pipe', 'pipe', 'ipc'],
 		env: env
 	});