Bernd Schmidt writes: The following patch is needed for libc to be able to emulate poll with ppoll.

libc/sysdeps/linux/common/ppoll.c

@@ -22,6 +22,8 @@
 
 #ifdef __NR_ppoll
 
+libc_hidden_proto(ppoll)
+
 # define __NR___libc_ppoll __NR_ppoll
 static inline
 _syscall4(int, __libc_ppoll, struct pollfd *, fds,
@@ -43,5 +45,6 @@ ppoll (struct pollfd *fds, nfds_t nfds, const struct timespec *timeout,
 
   return __libc_ppoll(fds, nfds, timeout, sigmask);
 }
+libc_hidden_def(ppoll)
 
 #endif