Define atomic macros for C++ project to fix nuttx/spinlock.h compilat…

[teamprof]

Issue

Fail to build Pi Pico NuttX C++ project with SMP feature as <nuttx/spinlock.h> is a C header that uses raw macro calls (atomic_cmpxchg_acquire(...)).

Summary

Failed to build a Pi Pico C++ project with SMP enabled due to the missing atomic marcos for nuttx/spinlock.h
Define atomic macros for C++ project to fix nuttx/spinlock.h compilation issue

Impact

Failed to build a Pi Pico (RP2040) C++ project with the SMP feature enabled. Notably, robust SMP support on the RP2040 is a key feature that encourages developers to choose NuttX over other RTOS options.

Testing

Follow the steps on https://github.com/teamprof/arduprof-template/tree/main/pico-nuttx-app to create a C++ project:
git clone --recurse-submodules https://github.com/teamprof/arduprof-template.gif
cd arduprof-template/pico-nuttx-app
ln -s ../src apps/arduprof
cd nuttx
./tools/configure.sh -l ../src/boards/arm/rp2040/raspberrypi-pico/configs/smp
make

Launch a Serial Terminal and connect to Pico's GPIO0/1 at 115200bps
Run "arduprof" under nsh in the terminal

Before

After

minicom screenshot of running on Pi Pico

[github-actions]

MemBrowse Memory Report

No memory changes detected for:

• arduino-mega2560
• esp32-devkitc
• hifive1-revb
• mirtoo
• qemu-armv8a
• qemu-intel64
• rx65n-rsk2mb
• s698pm-dkit
• stm32-nucleo-f103rb

[acassis]

@xiaoxiang781216 PTAL

[cederom]

Thank you @teamprof :-)

• Please fix the git commit according to https://nuttx.apache.org/docs/latest/contributing/guide.html#commit-requirements.
• Please fix minor code forma issue reported by ci/checkpatch (see https://nuttx.apache.org/docs/latest/contributing/coding_style.html).
• PR description does not seem to cover use case in NuttX, please update (specifically description + testing section).