libmetal(cmake): set HAVE_STDATOMIC_H default true in NuttX platform

[wyr-7]

there is no need to use cmake include detection under NuttX platform

[arnopo]

Seems not a good idea to force HAVE_STDATOMIC_H here
what about ujsrt having

elseif (NOT "${CMAKE_SYSTEM_NAME}" STREQUAL "NuttX")

  # TODO: fix for find_path() to detect stdatomic.h
  # find_path (HAVE_STDATOMIC_H stdatomic.h)
  set (_saved_cmake_required_flags ${CMAKE_REQUIRED_FLAGS})
  set (CMAKE_REQUIRED_FLAGS "-c" CACHE STRING "")
  check_include_files (stdatomic.h HAVE_STDATOMIC_H)
  set (CMAKE_REQUIRED_FLAGS ${_saved_cmake_required_flags})

endif ()

[xuxin930]

NuttX platform supports builtin atomic and toolchain atomic.
The reason why CMAKE_REQUIRED_FLAGS cannot be used here is because this cache will destroy the CMake build of the integrated platform

[arnopo]

My point here is that HAVE_STDATOMIC_H is probably defined in NuttX so the set(HAVE_STDATOMIC_H true) seems redundant.
Exclude the cmake code related to CMAKE_REQUIRED_FLAGS could be sufficient

[xuxin930]

My point here is that HAVE_STDATOMIC_H is probably defined in NuttX so the set(HAVE_STDATOMIC_H true) seems redundant. Exclude the cmake code related to CMAKE_REQUIRED_FLAGS could be sufficient

HAVE_STDATOMIC_H is the result of following this check check_include_files (stdatomic.h HAVE_STDATOMIC_H).

sure, thanks for your suggestion @arnopo .
Let's check for non-NuttX platforms in the if block

[wyr-7]

@arnopo Thansk, I have updated it according to @xuxin930 comment.

[arnopo]

LGTM

[edmooring]

Looks good to go.

[arnopo]

I have fixed the commit subject that was not up to date