cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration sys_wait/waitid.c -o sys_wait/waitid -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lintl -liconv
sys_wait/waitid.c: In function ‘main’:
sys_wait/waitid.c:36:14: error: implicit declaration of function ‘waitid’; did you mean ‘waitpid’? [-Wimplicit-function-declaration]
   36 |         if ( waitid(P_PID, children[0], &info, 0) < 0 )
      |              ^~~~~~
      |              waitpid
sys_wait/waitid.c:36:21: error: ‘P_PID’ undeclared (first use in this function)
   36 |         if ( waitid(P_PID, children[0], &info, 0) < 0 )
      |                     ^~~~~
sys_wait/waitid.c:36:21: note: each undeclared identifier is reported only once for each function it appears in
sys_wait/waitid.c:50:21: error: ‘P_PGID’ undeclared (first use in this function)
   50 |         if ( waitid(P_PGID, getpgid(0), &info, 0) < 0 )
      |                     ^~~~~~
sys_wait/waitid.c:74:21: error: ‘P_ALL’ undeclared (first use in this function)
   74 |         if ( waitid(P_ALL, 0, &info, 0) < 0 )
      |                     ^~~~~