cc -pipe -O   -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations termios/FF0.c -o termios/FF0 -D_POSIX_C_SOURCE=202405L  -lm -lpthread -lrt  -lrt -lcrypt
termios/FF0.c:8:17: error: 'FF0' undeclared here (not in a function)
 int const foo = FF0;
                 ^~~