RT-Thread/rt-thread: https://github.com/RT-Thread/rt-thread.git @ 4e40129e57f8c507514fc981fa742820a1a08e8a

iysheng a2a7f3c2d9 [components][rtc] Add RTC framework V2.0 to simplify RTC registration process		4 vuotta sitten
..
none-gcc	cb7fa8fcea implement pid_t gettid(void)	4 vuotta sitten
sys	1627597fcc remove _TIMESPEC_DEFINED	4 vuotta sitten
SConscript	ae66d82624 update sconscript	4 vuotta sitten
dirent.h	f9ba41f4c2 更改libc目录为common 以及 none-gcc	4 vuotta sitten
readme.md	f9ba41f4c2 更改libc目录为common 以及 none-gcc	4 vuotta sitten
stdlib.c	3c05a4e719 [compoenets] auto & manual formatted	5 vuotta sitten
termios.h	3c05a4e719 [compoenets] auto & manual formatted	5 vuotta sitten
time.c	a2a7f3c2d9 [components][rtc] Add RTC framework V2.0 to simplify RTC registration process	4 vuotta sitten
unistd.c	19347ed454 [libc][unistd] 完善isatty()	4 vuotta sitten

Attentions

This folder is "common" for all toolchains.
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'])
```