cc -O2 -pipe  -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/_SC_DEVICE_CONTROL.c -o unistd/_SC_DEVICE_CONTROL -D_POSIX_C_SOURCE=202405L  -lm -lpthread 
unistd/_SC_DEVICE_CONTROL.c:2:17: error: use of undeclared identifier '_SC_DEVICE_CONTROL'
int const foo = _SC_DEVICE_CONTROL;
                ^
1 error generated.