clang -O2  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations termios/CR0.c -o termios/CR0 -D_POSIX_C_SOURCE=202405L  -lm  -lintl
termios/CR0.c:8:17: error: use of undeclared identifier 'CR0'
int const foo = CR0;
                ^
1 error generated.