clang 14 warns about its use. It is being deprecated by the working
group for the programming language C: "The macro ATOMIC_VAR_INIT is
basically useless for the purpose for which it was designed"
Ref: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2886.htm
Reported-by: Tatsuhiro Tsujikawa
Fixes#9041Closes#9042