* [net] adjust folder structure
- 将lwip相关的文件夹，移入lwip文件夹
- Kconfig 分散到at netdev lwip sal文件夹中，使用menuconfig代替menu

* add references

* [dmodule] add <fcntl.h>

* [fix][components][utilities]adjust the order of compiler macros
Signed-off-by: NWillianChan <chentingwei@rt-thread.com>

* [modify][components][utilities]This PR complies with RT-Thread code specification
Signed-off-by: NWillianChan <chentingwei@rt-thread.com>

* [cpu] 增加ARCH_CPU_BIG_ENDIAN
- 之前RT_USING_BIG_ENDIAN的命名并不合理，予以替换为ARCH_CPU_BIG_ENDIAN
- 删除一处多余的ARCH_CPU_64BIT
- 整理了libcpu/Kconfig的格式

* [libcpu][Kconfig] Cortex-M4&7 select ARCH_ARM_CORTEX_FPU

* revert last commit

* [posix][io]整理posix/io文件夹
- 将select.c移入到poll文件夹
- 将libc.c移入到tty文件夹，isatty函数归并到libc.c中, termios并入tty文件夹中
- 整理Sconscript
Signed-off-by: Meco Man <920369182@qq.com>

* [libc][newlib]调整文件夹结构

- 移除2.0.2，该版本存在几个重要的bug，已经在2.0.3中修复，作者强烈建议更新
- 将部分bsp由2.0.2调整为2.0.3

* [add] the function realization of signal for posix.
* [update] the posix support for armclang.
* [add] the new macro "RT_USING_POSIX_TIMER".
* [modify] select "RT_USING_SOFT_TIMER" when use posix'timer.
* [bug] optimize the logic for the "time_xxx" functions.
* [modify] use "RT_USING_POSIX_TIMER" to protect the macro definition.
* [modify] error code when except happened.
* [delete] the "environ" is useless at this time.

- 删除啰嗦的代码
related: https://github.com/RT-Thread/rt-thread/issues/3046

* [lwip] 修复ioctl与lwip socket定义冲突的问题

* format sys/ioctl.h

* [console] 解决在没有定义RT_USING_DEVICE的情况下使用device报错的问题

* format codes

* [libc] 整理格式

* refresh projects