版本控制规范：https://semver.org/
目前的版本子号不是很规范，其中RT_VERSION甚至和VS那边造成了冲突
```c
/* RT-Thread version information */
#define RT_VERSION 4L /**< major version number */
#define RT_SUBVERSION 1L /**< minor version number */
#define RT_REVISION 1L /**< revise version number */
```
参考ESP32：
```c
/** Major version number (X.x.x) */
#define ESP_ARDUINO_VERSION_MAJOR 2
/** Minor version number (x.X.x) */
#define ESP_ARDUINO_VERSION_MINOR 0
/** Patch version number (x.x.X) */
#define ESP_ARDUINO_VERSION_PATCH 3
```
建议改成：
```c
/* Major version number (X.x.x) */
#define RT_VERSION_MAJOR 4
/* Minor version number (x.X.x) */
#define RT_VERSION_MINOR 2
/* Patch version number (x.x.X) */
#define RT_VERSION_PATCH 0
```
* [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.
- Backward compatible with existing function-pointer based hooking method
- Using RT_USING_HOOK as an on/off switch
- Introducing a new low-overhead macro-based hooking method
1. Add RTGRAPHIC_CTRL_PAN_DISPLAY and RTGRAPHIC_CTRL_WAIT_VSYNC control command.
2. Add calibration data of 480x272 ADC touching.
3. Add 480x272 LCD panel menu option and driver.
4. Update lv_conf.h.
* [kernel][mem] Multiple instances of small memory allocation algorithm
* [kernel][mem] Change small memory management algorithm memory header flag
* [kernel][mem] Fix assertion problem
* [kernel][slab] Multiple instances of slab memory management algorithm
* [kernel][memheap] Remove rt_malloc/rt_free/rt_realloc and other related memory interfaces
* [kernel][mem] Clean up memory space of small memory management objects
* [kernel][kservice] Add memory application interface and thread protection interface
* [kernel][kservice] Fix function return value problem
* [kernel][memheap] Optimize memheaptrace print
* [kernel][memheap] Support best mode
* [kernel][memory] Remove semaphore lock
* [kernel][memheap] Add locked flag
* [kernel][memory] Support malloc memory in interrupt
* [kernel][memheap] Add 'memheapcheck' cmd
* [kernel][mem] Fix failure to request full memory
* [kernel][memheap] Fix compilation warning
* [kernel][mem] Fix mem realloc ASSERT
* [examples][testcases] Add small mem testcase
* [examples][mem_tc] Modify test memory size
* [examples][testcases] Add slab memory management algorithm test case
* [examples][testcases] fix small memory management algorithm test case
* [kernel][memory] Adjusting memory allocation algorithm object definition and interface
* [kernel][memory] Fix compilation warning
* [examples][utest] Fix mem test case
* [examples][utest] fix slab test case
* [utest][testcases] Shorten test time
* [kernel][memory] Formatting code
* [examples][utest] Adjust test run time
* [examples][utest] Formatting code
* [bsp] update all rtconfig.h
Bernard Xiong
Man, Jianting (Meco)
Yunjie Gu
lpy
YuQi
xiangxistu
thewon86
Judd
Tangyuxin
guo
Wayne
张世争
wanghaijing
Gabriel Wang
Wayne Lin
armink
马志远
lymzzyh