cc -O2 -pipe  -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/_CS_V8_ENV.c -o unistd/_CS_V8_ENV -D_POSIX_C_SOURCE=202405L  -lm -lpthread 
unistd/_CS_V8_ENV.c:2:17: error: use of undeclared identifier '_CS_V8_ENV'
int const foo = _CS_V8_ENV;
                ^
1 error generated.