bugfix: Looking for “WIN” inside “Darwin” will give positive results.

To put it differently, to avoid OSX machines being identified as windows boxes, “darwin” should be evaluated *before* “win”.

lib/SimpleSAML/Utils/System.php

@@ -31,12 +31,12 @@ class System
         if (stristr(PHP_OS, 'LINUX')) {
             return self::LINUX;
         }
-        if (stristr(PHP_OS, 'WIN')) {
-            return self::WINDOWS;
-        }
         if (stristr(PHP_OS, 'DARWIN')) {
             return self::OSX;
         }
+        if (stristr(PHP_OS, 'WIN')) {
+            return self::WINDOWS;
+        }
         if (stristr(PHP_OS, 'BSD')) {
             return self::BSD;
         }