This issue causes fstat & lseek not correct.

I have to mention that this bug is introduced by myself, in the last
commit <fd07f30f> to dfs_nfs.c

more infomation:
http://www.rt-thread.org/phpBB3/topic2965.html

_TIME_T_DEFINED was pre-defined in order to build jffs2 with VC.
While it may cause many side effects.

found by haitao5198
clear mount parition device talbe when jffs2 mount falied

found by haitao52198
URL:http://www.rt-thread.org/phpBB3/viewtopic.php?f=3&t=3112&p=17153#p17153

fix memory leak in dfs_elm.c and umount fatfs when mount fatfs fails (this bug leads to mkfs failure in linux)

elm fatfs support mkfs with no need to  run dfs_mount elm first; and can mount/umount/mkfs without reset any more

remove the drivers in uffs/nand which is already out of date. now you can look simulator to explore how to use uffs on nand flash or Realtouch demo code on github

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@2576 bbd45198-f89e-11dd-88c7-29a3b14d5316

1. fix bug in uffs_nandif.c to work with mtd nand driver; 2)clean code in uffs_nandif.c and dfs_uffs.h

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@2575 bbd45198-f89e-11dd-88c7-29a3b14d5316

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@2558 bbd45198-f89e-11dd-88c7-29a3b14d5316

now we can create file or directory  on NFS server both with FreeNFS on windows and nfs-server on linux

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@2556 bbd45198-f89e-11dd-88c7-29a3b14d5316

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@2545 bbd45198-f89e-11dd-88c7-29a3b14d5316

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@2497 bbd45198-f89e-11dd-88c7-29a3b14d5316

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@2496 bbd45198-f89e-11dd-88c7-29a3b14d5316