cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration pthread/pthread_testcancel.c -o pthread/pthread_testcancel -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lintl -liconv
pthread/pthread_testcancel.c: In function ‘start’:
pthread/pthread_testcancel.c:12:17: error: implicit declaration of function ‘pthread_testcancel’; did you mean ‘pthread_detach’? [-Wimplicit-function-declaration]
   12 |                 pthread_testcancel();
      |                 ^~~~~~~~~~~~~~~~~~
      |                 pthread_detach
pthread/pthread_testcancel.c: In function ‘main’:
pthread/pthread_testcancel.c:21:23: error: implicit declaration of function ‘pthread_cancel’; did you mean ‘pthread_once’? [-Wimplicit-function-declaration]
   21 |         if ( (errno = pthread_cancel(thread)) )
      |                       ^~~~~~~~~~~~~~
      |                       pthread_once
pthread/pthread_testcancel.c:26:24: error: ‘PTHREAD_CANCELED’ undeclared (first use in this function); did you mean ‘PTHREAD_NULL’?
   26 |         if ( result != PTHREAD_CANCELED )
      |                        ^~~~~~~~~~~~~~~~
      |                        PTHREAD_NULL
pthread/pthread_testcancel.c:26:24: note: each undeclared identifier is reported only once for each function it appears in