fix ssize_t redefinition error when using minilibc

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1160 bbd45198-f89e-11dd-88c7-29a3b14d5316

components/dfs/filesystems/nfs/rpc/types.h

@@ -62,10 +62,13 @@ typedef int bool_t;
 typedef int enum_t;
 
 #ifndef RT_USING_NEWLIB
-typedef rt_int32_t  ssize_t;
 typedef unsigned long dev_t;
 #endif
 
+#if !defined(RT_USING_NEWLIB) && !defined(RT_USING_MINILIBC)
+typedef rt_int32_t  ssize_t;
+#endif
+
 /* This needs to be changed to uint32_t in the future */
 typedef unsigned long rpcprog_t;
 typedef unsigned long rpcvers_t;