cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration pthread/pthread_condattr_getclock.c -o pthread/pthread_condattr_getclock -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread  -liconv
pthread/pthread_condattr_getclock.c:14:16: error: call to undeclared function 'pthread_condattr_getclock'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   14 |         if ( (errno = pthread_condattr_getclock(&attr, &clock_id)) )
      |                       ^
pthread/pthread_condattr_getclock.c:14:16: note: did you mean 'pthread_condattr_destroy'?
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/pthread.h:324:5: note: 'pthread_condattr_destroy' declared here
  324 | int pthread_condattr_destroy(pthread_condattr_t *);
      |     ^
1 error generated.