btrfs-progs: build: add missing symbols to libbtrfs

Several people reported build breakage of snapper, due to missing
symbols in libbtrfs.so. Move the objects to the library objects, now we
don't have to worry about the new exports as the libbtrfs.sym is
unchanged. And there are no new .h files being exported though there are
the .o files in the library.

Issue: #214
Link: https://github.com/openSUSE/snapper/issues/500
Signed-off-by: David Sterba <dsterba@suse.com>

Makefile

@@ -131,16 +131,14 @@ CHECKER_FLAGS := -include $(check_defs) -D__CHECKER__ \
 	-D__CHECK_ENDIAN__ -Wbitwise -Wuninitialized -Wshadow -Wundef \
 	-U_FORTIFY_SOURCE -Wdeclaration-after-statement -Wdefault-bitfield-sign
 
-objects = ctree.o disk-io.o extent-tree.o print-tree.o \
-	  root-tree.o dir-item.o file-item.o inode-item.o inode-map.o \
-	  volumes.o common/utils.o repair.o \
-	  qgroup.o free-space-cache.o kernel-lib/list_sort.o props.o \
+objects = dir-item.o inode-map.o \
+	  qgroup.o kernel-lib/list_sort.o props.o \
 	  kernel-shared/ulist.o check/qgroup-verify.o backref.o common/string-table.o \
 	  common/task-utils.o \
-	  inode.o file.o find-root.o free-space-tree.o common/help.o send-dump.o \
-	  common/fsfeatures.o kernel-lib/tables.o kernel-lib/raid56.o transaction.o \
-	  delayed-ref.o common/format-output.o common/path-utils.o \
-	  common/device-utils.o common/device-scan.o
+	  inode.o file.o find-root.o common/help.o send-dump.o \
+	  common/fsfeatures.o \
+	  common/format-output.o \
+	  common/device-utils.o
 cmds_objects = cmds/subvolume.o cmds/filesystem.o cmds/device.o cmds/scrub.o \
 	       cmds/inspect.o cmds/balance.o cmds/send.o cmds/receive.o \
 	       cmds/quota.o cmds/qgroup.o cmds/replace.o check/main.o \
@@ -152,7 +150,13 @@ cmds_objects = cmds/subvolume.o cmds/filesystem.o cmds/device.o cmds/scrub.o \
 libbtrfs_objects = send-stream.o send-utils.o kernel-lib/rbtree.o btrfs-list.o \
 		   kernel-lib/radix-tree.o extent-cache.o extent_io.o \
 		   kernel-lib/crc32c.o common/messages.o \
-		   uuid-tree.o utils-lib.o common/rbtree-utils.o
+		   uuid-tree.o utils-lib.o common/rbtree-utils.o \
+		   ctree.o disk-io.o extent-tree.o delayed-ref.o print-tree.o \
+		   free-space-cache.o root-tree.o volumes.o transaction.o \
+		   free-space-tree.o repair.o inode-item.o file-item.o \
+		   kernel-lib/raid56.o kernel-lib/tables.o \
+		   common/device-scan.o common/path-utils.o \
+		   common/utils.o libbtrfsutil/subvolume.o libbtrfsutil/stubs.o
 libbtrfs_headers = send-stream.h send-utils.h send.h kernel-lib/rbtree.h btrfs-list.h \
 	       kernel-lib/crc32c.h kernel-lib/list.h kerncompat.h \
 	       kernel-lib/radix-tree.h kernel-lib/sizes.h kernel-lib/raid56.h \