[FIXED JENKINS-17343]

Don't break Windows XP, fall back gracefully to no-op.
(cherry picked from commit a016f3d)

Conflicts:
	changelog.html

core/src/main/java/hudson/Util.java

@@ -1065,6 +1065,9 @@ public static void createSymlink(File baseDir, String targetPath, String symlink
                         return;
                     }
                     throw e;
+                } catch (UnsatisfiedLinkError e) {
+                    // not available on this Windows
+                    return;
                 }
             } else {
                 String errmsg = "";

core/src/main/java/hudson/util/jna/Kernel32Utils.java

@@ -80,6 +80,10 @@ public static int getWin32FileAttributes(File file) throws IOException {
      * @param target
      *      If relative, resolved against the location of the symlink.
      *      If absolute, it's absolute.
+     * @throws UnsatisfiedLinkError
+     *      If the function is not exported by kernel32.
+     *      See http://msdn.microsoft.com/en-us/library/windows/desktop/aa363866(v=vs.85).aspx
+     *      for compatibility info.
      */
     public static void createSymbolicLink(File symlink, String target, boolean dirLink) throws IOException {
         if (!Kernel32.INSTANCE.CreateSymbolicLinkW(