fix compile error using gcc compiler

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@741 bbd45198-f89e-11dd-88c7-29a3b14d5316

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

@@ -38,9 +38,12 @@
 #include <lwip/sockets.h>
 
 #include <string.h>
+
+#ifndef RT_USING_MINILIBC
 typedef unsigned int u_int;
 typedef unsigned char u_char;
 typedef unsigned long u_long;
+#endif
 
 typedef rt_int8_t   int8_t;
 typedef rt_uint8_t  uint8_t;