perf_counter

      - Avoid time roll-back in some rare cases
      - Add macros for protoThread
      - Some minor changes

      Release v2.3.3
      - Enhance foreach() and with() with __typeof__()
      - Always use systick_wrapper_gnu.s when Arm Compiler 6 is detected
      - Some minor fixes

      Release v2.3.2
      - Adds __perfc_sync_barrier__() and improves __cycleof__()
      - Some minor fixes

      Release v2.3.1
      - Fixed PMU-SysTick-overflow-miscounting issue
      - Other minor changes.

      Release v2.3.0
      - Support porting to a different architecture
      - Support Armv8.1-m PMU
          * Add __cpu_perf__() for CPI and L1 DCache miss rate
      - Some other minor changes.

      - Add support for RT-Thread-nano
      - Add an API for checking stack overflow
      - Improve the support for the Arm Compiler 6.21
      - Other minor updates

      - Mitigate time-rolling-back issue when calling get_system_ticks in exception handlers that have higher priorities than the SysTick_Handler.
      - Other minor updates

      - Add __cpu_time__
      - Support reconfiguring the SysTick
      - Suppress warnings
      - Other minor updates

      - Update perfc_is_time_out_ms and perf_is_time_out_us

      - Enhance Timer Services
      - Other minor changes

      - Update stop_cycle_counter prototype to solve return-value-overflow issue
      - Provide timer service for EventRecorder automatically
      - Remove the bundle from cmsis-pack

      - Add Coremark

      - Fix the source variant support for Armv8-M processors
      - Other minor fixes

      - Fix the support for RT-Thread
      - Improve the way to import systick wrapper
      - Add get_system_us to avoid 64bit integer divider.
      - Minor Update

      - Improve delay accuracy
      - Fix RT-Thread stack-fully-used issue
      - introduce macro __PERF_COUNTER_CFG_USE_SYSTICK_WRAPPER__

      - Add RT-Thread Package
      - Add new API update_perf_counter() for notifying perf_counter that SystemCoreClock has been updated
      - Add a macro __perf_counter_printf__ to retarget printf
      - Add a macor __PERF_COUNT_PLATFORM_SPECIFIC_HEADER__ for people to insert a platform specific header file.
      - Add Doxygen
      - Other minor changes

      - Add support for Cortex-M85, Star-MC1 and all other Armv8.1-M processors
      - Update Readme

      - Mitigate some clang warnings
      - Minor update for RTOS support

      - Fix CONNECT macro cannot connect two parameters issue.
      - Add UNUSED_PARAM
      - Add support for C++ env
      - Other minor updates

      - Add API get_system_ms() to avoid int64_t divide operation.
      - Add API delay_ms()

      - Add preprocessing in perf_counter.h to detect whether GNU extension is enabled or not.
      - Enhance RTOS support
      - Add macro __PERF_COUNTER__ in RTE_Components.h for compile-time detection.

      - Fix a bug found in __cycleof__. The __cycle_counter__ was not updated with the measure result.
      - Add macros for version info.