cc -O2 -pipe -pthread -I/usr/local/include  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations pthread/PTHREAD_NULL.c -o pthread/PTHREAD_NULL -D_POSIX_C_SOURCE=202405L  -lm -lpthread -lrt -L/usr/local/lib  -lintl -lstdthreads -lcrypt
pthread/PTHREAD_NULL.c:2:24: error: use of undeclared identifier 'PTHREAD_NULL'
    2 | pthread_t  const foo = PTHREAD_NULL;
      |                        ^
1 error generated.