btrfs-progs: build: add missing objects to libbtrfs

A user reports that some symbols are missing from libbtrfs, eg.
radix_tree_init. This is correct and there are few more. The headers
exported through the library all need the respective object files.

The sources are GPL so is libbtrfs, which is known

Issue: #205
Signed-off-by: David Sterba <dsterba@suse.com>

Makefile

@@ -131,9 +131,9 @@ 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 kernel-lib/radix-tree.o extent-tree.o print-tree.o \
+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 \
-	  extent-cache.o extent_io.o volumes.o common/utils.o repair.o \
+	  volumes.o common/utils.o repair.o \
 	  qgroup.o free-space-cache.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 \
@@ -150,6 +150,7 @@ cmds_objects = cmds/subvolume.o cmds/filesystem.o cmds/device.o cmds/scrub.o \
 	       cmds/inspect-dump-super.o cmds/inspect-tree-stats.o cmds/filesystem-du.o \
 	       mkfs/common.o check/mode-common.o check/mode-lowmem.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
 libbtrfs_headers = send-stream.h send-utils.h send.h kernel-lib/rbtree.h btrfs-list.h \