tools/liblockdep: Build liblockdep from tools/Makefile

add targets to build liblockdep with
  make -C tools liblockdep
like the way other stuff under tools/ can be built

Signed-off-by: S. Lockwood-Childs <sjl@vctlabs.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
diff --git a/tools/Makefile b/tools/Makefile
index bcae806..9a617ad 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -44,6 +44,9 @@
 cgroup firewire hv guest usb virtio vm net: FORCE
 	$(call descend,$@)
 
+liblockdep: FORCE
+	$(call descend,lib/lockdep)
+
 libapikfs: FORCE
 	$(call descend,lib/api)
 
@@ -91,6 +94,9 @@
 cgroup_clean hv_clean firewire_clean lguest_clean usb_clean virtio_clean vm_clean net_clean:
 	$(call descend,$(@:_clean=),clean)
 
+liblockdep_clean:
+	$(call descend,lib/lockdep,clean)
+
 libapikfs_clean:
 	$(call descend,lib/api,clean)