* correct descriptions

correct descriptions in ipc.c and timer.c
Co-authored-by: NStanley <stanleylwinn@gmail.com>

* Update ipc.c

Parameter name standardization
Co-authored-by: NStanley <stanleylwinn@gmail.com>

Resolved feedbacks

dd descriptions for rt_mq_recv and rt_sem_take timeout parameters

* [kconfig] add 64bit default value for stack size. set tick HZ as 1000 by default

* 用RT_KSERVICE_USING_STDLIB_MEMXXX代替RT_KSERVICE_USING_STDLIB_MEMCP/MEMSET
将RT_KSERVICE_USING_STDLIB设置为默认开启

* 优化rt_kprintf支持longlong的能力，默认在64位CPU为开启状态
RT_PRINTF_LONGLONG命名不规范，更改为RT_KPRINTF_USING_LONGLONG

* fix commit error

* fix error

* 优化 system 函数

* RT_KSERVICE_USING_STDLIB_MEMXXX->RT_KSERVICE_USING_STDLIB_MEMORY

When we create thread A by rt_thread_init but do
    not init the thread object,and then create thread
    B in the thread A,it maybe crash.

* [add] src/clock.c add hook for rt_tick_increase

* [fix] clock.c rt_tick_incerase hook function

* Update clock.c
Co-authored-by: Nguo <guozhanxin@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

* [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.

* [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