clang -O2  -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  -lintl
poll/ppoll.c:50:14: error: implicit declaration of function 'ppoll' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
        if ( (ret = ppoll(pfds, 1, &timeout, &oldset)) < 0 )
                    ^
poll/ppoll.c:50:14: note: did you mean 'poll'?
/usr/include/poll.h:83:5: note: 'poll' declared here
int     poll(struct pollfd *, nfds_t, int);
        ^
1 error generated.