btrfs-progs: build, add basic build test for library

Basic test based on snapper code that uses the send stream API.

Signed-off-by: David Sterba <dsterba@suse.cz>
btrfs-progs: build, add make target for a build test

A quick check that everything still builds.

Signed-off-by: David Sterba <dsterba@suse.cz>
btrfs-progs: build, gather utilities that are not built by default

Add them to build test and to clean rules.

Signed-off-by: David Sterba <dsterba@suse.cz>
btrfs-progs: build, update the clean rule

Remove duplicate files, add extra progs, add library test binaries.

Signed-off-by: David Sterba <dsterba@suse.cz>
btrfs-progs: update .gitignore

Signed-off-by: David Sterba <dsterba@suse.cz>
btrfs-progs: fix compiler warning

gcc 4.9.0 gives warnings about possibly uninitialized values when
compiling with function inlining and optimization level two enabled
(CFLAGS="-finline-functions -O2").

Initializing the values fixes the warning. Hope this is correct.

Signed-off-by: Christian Hesse <mail@eworm.de>
Signed-off-by: David Sterba <dsterba@suse.cz>