cc -O2 -pipe  -pthread  -Wall -Wextra -Werror=implicit-function-declaration pthread/pthread_mutexattr_setrobust.c -o pthread/pthread_mutexattr_setrobust -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread 
pthread/pthread_mutexattr_setrobust.c:12:16: error: call to undeclared function 'pthread_mutexattr_setrobust'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
   12 |         if ( (errno = pthread_mutexattr_setrobust(&attr, PTHREAD_MUTEX_ROBUST)) )
      |                       ^
pthread/pthread_mutexattr_setrobust.c:12:51: error: use of undeclared identifier 'PTHREAD_MUTEX_ROBUST'; did you mean 'PTHREAD_MUTEX_NORMAL'?
   12 |         if ( (errno = pthread_mutexattr_setrobust(&attr, PTHREAD_MUTEX_ROBUST)) )
      |                                                          ^~~~~~~~~~~~~~~~~~~~
      |                                                          PTHREAD_MUTEX_NORMAL
/usr/include/pthread.h:171:2: note: 'PTHREAD_MUTEX_NORMAL' declared here
  171 |         PTHREAD_MUTEX_NORMAL            = 3,    /* No error checking */
      |         ^
pthread/pthread_mutexattr_setrobust.c:15:16: error: call to undeclared function 'pthread_mutexattr_getrobust'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
   15 |         if ( (errno = pthread_mutexattr_getrobust(&attr, &robustness)) )
      |                       ^
pthread/pthread_mutexattr_setrobust.c:17:21: error: use of undeclared identifier 'PTHREAD_MUTEX_ROBUST'; did you mean 'PTHREAD_MUTEX_NORMAL'?
   17 |         if ( robustness != PTHREAD_MUTEX_ROBUST )
      |                            ^~~~~~~~~~~~~~~~~~~~
      |                            PTHREAD_MUTEX_NORMAL
/usr/include/pthread.h:171:2: note: 'PTHREAD_MUTEX_NORMAL' declared here
  171 |         PTHREAD_MUTEX_NORMAL            = 3,    /* No error checking */
      |         ^
4 errors generated.