cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration pthread/pthread_atfork.c -o pthread/pthread_atfork -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lintl -liconv
pthread/pthread_atfork.c: In function ‘main’:
pthread/pthread_atfork.c:50:23: error: implicit declaration of function ‘pthread_atfork’; did you mean ‘pthread_join’? [-Wimplicit-function-declaration]
   50 |         if ( (errno = pthread_atfork(prepare, parent, child)) )
      |                       ^~~~~~~~~~~~~~
      |                       pthread_join