cc -pthread   -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations sys_mman/MS_SYNC.c -o sys_mman/MS_SYNC -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt  -lintl -liconv
sys_mman/MS_SYNC.c:8:17: error: ‘MS_SYNC’ undeclared here (not in a function)
    8 | int const foo = MS_SYNC;
      |                 ^~~~~~~