remove sprint, malloc, free function link when using Keil MDK compiler.

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1549 bbd45198-f89e-11dd-88c7-29a3b14d5316

components/external/jpeg/jerror.c

@@ -32,6 +32,9 @@
 #define EXIT_FAILURE  1
 #endif
 
+/* sprintf wrapper for RT-Thread */
+#include <rtthread.h>
+#define sprintf	rt_sprintf
 
 /*
  * Create the message string table.

components/external/jpeg/jmemnobs.c

@@ -25,6 +25,10 @@ extern void * malloc JPP((size_t size));
 extern void free JPP((void *ptr));
 #endif
 
+/* memory wrapper for RT-Thread */
+#include <rtthread.h>
+#define malloc rt_malloc
+#define free rt_free
 
 /*
  * Memory allocation and freeing are controlled by the regular library