New is_windows_os helper added.

Author: dmitry-ivanov

src/classes/Artisan/Command.php

@@ -31,7 +31,7 @@ public function runInBackground()
 
     protected function composeForRunInBackground()
     {
-        if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
+        if (is_windows_os()) {
             return "start /B {$this->composeForRun()}";
         }
 

src/system.php

@@ -0,0 +1,8 @@
+<?php
+
+if (!function_exists('is_windows_os')) {
+    function is_windows_os()
+    {
+        return (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN');
+    }
+}