fix the compiling error.

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1040 bbd45198-f89e-11dd-88c7-29a3b14d5316

components/libc/minilibc/qsort.c

-#include <sys/cdefs.h>
 #include <sys/types.h>
-
 #include <stdlib.h>
 
 static void exch(char* base,size_t size,size_t a,size_t b) {