RT-Thread-Studio/sdk-rt-thread-source-code: https://github.com/RT-Thread-Studio/sdk-rt-thread-source-code.git @ v4.0.3

yaxing.chen c0257098b9 release rt-thread v4.0.3		4 vuotta sitten
..
sys	c0257098b9 release rt-thread v4.0.3	4 vuotta sitten
SConscript	c0257098b9 release rt-thread v4.0.3	4 vuotta sitten
readme.md	c0257098b9 release rt-thread v4.0.3	4 vuotta sitten
termios.h	c0257098b9 release rt-thread v4.0.3	4 vuotta sitten
time.c	c0257098b9 release rt-thread v4.0.3	4 vuotta sitten
unistd.c	c0257098b9 release rt-thread v4.0.3	4 vuotta sitten

Attentions

This folder is "common" for armlibc newlibc and dlib. It's not "common" for minilibc.
If you want to add new .c files, please do not forget to fix SConscript file too. eg:
```
if GetDepend('RT_USING_POSIX') == False:
    SrcRemove(src, ['unistd.c'])
```