Patch porting gcc v2 (#124)

* 更改编译器的Include路径，使得include时不需要加`<libc/src/include/>`前缀

* 修改include路径

Co-authored-by: longjin <longjin@RinGoTek.cn>

user/apps/shell/cmd_test.c

@@ -1,8 +1,8 @@
 #include "cmd_test.h"
-#include <libc/src/stdio.h>
-#include <libc/src/stdlib.h>
-#include <libc/src/string.h>
-#include <libc/src/unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
 
 int shell_pipe_test(int argc, char **argv)
 {