cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations ftw/FTW_XDEV.c -o ftw/FTW_XDEV -D_POSIX_C_SOURCE=202405L  -lm -lpthread  -liconv
ftw/FTW_XDEV.c:8:17: error: use of undeclared identifier 'FTW_XDEV'
    8 | int const foo = FTW_XDEV;
      |                 ^
1 error generated.