[Kernel] Add device ops feature.

components/libc/compilers/newlib/libc.c

@@ -35,6 +35,8 @@
 #include <pthread.h>
 #endif
 
+int	_EXFUN(putenv,(char *__string));
+
 int libc_system_init(void)
 {
 #if defined(RT_USING_DFS) & defined(RT_USING_DFS_DEVFS)

components/libc/compilers/newlib/stdio.c

@@ -31,6 +31,8 @@
 
 #define STDIO_DEVICE_NAME_MAX   32
 
+int	_EXFUN(fileno, (FILE *));
+
 static FILE* std_console = NULL;
 
 int libc_stdio_set_console(const char* device_name, int mode)