[libc] 支持system函数

components/libc/compilers/common/stdlib.c

@@ -10,19 +10,26 @@
 
 #include <rtthread.h>
 
+#define DBG_TAG    "stdlib"
+#define DBG_LVL    DBG_INFO
+#include <rtdbg.h>
+
 void __rt_libc_exit(int status)
 {
     rt_thread_t self = rt_thread_self();
 
     if (self != RT_NULL)
     {
-        rt_kprintf("thread:%s exit:%d!\n", self->name, status);
+        LOG_E("thread:%s exit:%d!", self->name, status);
         rt_thread_control(self, RT_THREAD_CTRL_CLOSE, RT_NULL);
     }
 }
 
 int __rt_libc_system(const char *string)
 {
-    /* TODO */
+#ifdef RT_USING_MSH
+    extern int msh_exec(char *cmd, rt_size_t length);
+    msh_exec((char*)string, rt_strlen(string));
+#endif
     return 0;
 }