I had a little more time to explore this, and it turns out that the splice and vmsplice features are included only if the symbol _GNU_SOURCE is defined - in which case they compile correctly without the warning. That seems like a philosophical issue, so I think I should just withdraw the bug and file it under 'user misunderstanding'
-- Functions splice and vmsplice in glibc 2.5 not being declared for c progam https://launchpad.net/bugs/88091 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs