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 anni fa
..
sys	c0257098b9 release rt-thread v4.0.3	4 anni fa
SConscript	c0257098b9 release rt-thread v4.0.3	4 anni fa
readme.md	c0257098b9 release rt-thread v4.0.3	4 anni fa
termios.h	c0257098b9 release rt-thread v4.0.3	4 anni fa
time.c	c0257098b9 release rt-thread v4.0.3	4 anni fa
unistd.c	c0257098b9 release rt-thread v4.0.3	4 anni fa

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'])
```