/opt/IBM/openxlC/17.1.1/bin/ibm-clang -pthread  -Wall -Wextra -Werror=implicit-function-declaration poll/ppoll.c -o poll/ppoll -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -liconv -latomic
poll/ppoll.c:50:14: error: call to undeclared function 'ppoll'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
        if ( (ret = ppoll(pfds, 1, &timeout, &oldset)) < 0 )
                    ^
poll/ppoll.c:50:14: note: did you mean 'poll'?
/usr/include/sys/poll.h:167:12: note: 'poll' declared here
static int poll(void *__listptr, ulong_t __nfds, long __timeout)
           ^
1 error generated.