cc -pthread   -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  -lgdbm_compat -lcrypt -latomic
pthread/PTHREAD_NULL.c:2:24: error: ‘PTHREAD_NULL’ undeclared here (not in a function); did you mean ‘PTHREAD_CANCELED’?
    2 | pthread_t  const foo = PTHREAD_NULL;
      |                        ^~~~~~~~~~~~
      |                        PTHREAD_CANCELED