The two files send-stream and send-utils contain the implementations of
the exported API, which was just for send stream. This was the original
idea. That libbtrfs contains another 40 files was a result of
unclean/missing library design and had to be done that way to resolve
the symbols due to dependencies.
That the same files have been used for both internal and public library
has prevented refactoring and cleanups and was always a risk of breaking
something.
Make separate copy for libbtrfs utils and allow any cleanups and
reduction of number of build objects. The API hasn't changed since the
beginning so there's low risk of missing some fixes from the internal
code.
Signed-off-by: David Sterba <dsterba@suse.com>