cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration unistd/encrypt.c -o unistd/encrypt -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lcrypt -latomic
unistd/encrypt.c: In function ‘main’:
unistd/encrypt.c:15:9: error: implicit declaration of function ‘setkey’ [-Werror=implicit-function-declaration]
   15 |         setkey(key);
      |         ^~~~~~
unistd/encrypt.c:19:9: error: implicit declaration of function ‘encrypt’; did you mean ‘crypt’? [-Werror=implicit-function-declaration]
   19 |         encrypt(buffer, 0);
      |         ^~~~~~~
      |         crypt
cc1: some warnings being treated as errors