diff --git a/cmd/syncthing/memsize_unimpl.go b/cmd/syncthing/memsize_unimpl.go
index 704472379..caad7db49 100644
--- a/cmd/syncthing/memsize_unimpl.go
+++ b/cmd/syncthing/memsize_unimpl.go
@@ -13,7 +13,7 @@
 // You should have received a copy of the GNU General Public License along
 // with this program. If not, see <http://www.gnu.org/licenses/>.
 
-// +build freebsd openbsd
+// +build freebsd openbsd dragonfly
 
 package main