Buildfarm member caiman just came back online after some time AWOL, and
it's not happy. The problem evidently is that pg_rewind's copy_file_range
function conflicts with a recently added Linux system call:
http://man7.org/linux/man-pages/man2/copy_file_range.2.html
Looks like we'd better rename our function. Anybody have an idea
more creative than "pg_copy_file_range"?
(At some point somebody might want to think about fixing this function
so it can make use of the kernel call when available. But that's more
work than I care to do right now, and certainly more change than I'd want
to back-patch.)
regards, tom lane