clang -O2  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations ftw/FTW_XDEV.c -o ftw/FTW_XDEV -D_POSIX_C_SOURCE=202405L  -lm  -lintl
ftw/FTW_XDEV.c:8:17: error: use of undeclared identifier 'FTW_XDEV'
int const foo = FTW_XDEV;
                ^
1 error generated.