clang -O2  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/_CS_POSIX_V8_THREADS_CFLAGS.c -o unistd/_CS_POSIX_V8_THREADS_CFLAGS -D_POSIX_C_SOURCE=202405L  -lm  -lintl
unistd/_CS_POSIX_V8_THREADS_CFLAGS.c:2:17: error: use of undeclared identifier '_CS_POSIX_V8_THREADS_CFLAGS'
int const foo = _CS_POSIX_V8_THREADS_CFLAGS;
                ^
1 error generated.