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