cc -pthread   -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations stdlib/O_SYNC.c -o stdlib/O_SYNC -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt  -lintl -liconv
stdlib/O_SYNC.c:2:17: error: ‘O_SYNC’ undeclared here (not in a function)
    2 | int const foo = O_SYNC;
      |                 ^~~~~~