diff --git a/spot/ltsmin/Makefile.am b/spot/ltsmin/Makefile.am
index 8d5fcb1dc..e42bc730e 100644
--- a/spot/ltsmin/Makefile.am
+++ b/spot/ltsmin/Makefile.am
@@ -1,5 +1,5 @@
 ## -*- coding: utf-8 -*-
-## Copyright (C) 2011, 2013, 2014, 2015, 2016, 2017, 2018 Laboratoire de
+## Copyright (C) 2011, 2013, 2014, 2015, 2016, 2017, 2018, 2019 Laboratoire de
 ## Recherche et Developpement de l'Epita (LRDE).
 ##
 ## This file is part of Spot, a model checking library.
@@ -39,7 +39,7 @@ libspotltsmin_la_LIBADD = \
   $(top_builddir)/lib/libgnu.la \
   $(LIBLTDL) -lpthread
 libspotltsmin_la_LDFLAGS = -no-undefined $(SYMBOLIC_LDFLAGS)
-libspotltsmin_la_SOURCES = ltsmin.cc
+libspotltsmin_la_SOURCES = spins_interface.cc ltsmin.cc
 
 
 EXTRA_DIST = $(srcdir)/libspotltsmin.pc.in
diff --git a/spot/ltsmin/spins_interface.cc b/spot/ltsmin/spins_interface.cc
new file mode 100644
index 000000000..ce4e8f9a8
--- /dev/null
+++ b/spot/ltsmin/spins_interface.cc
@@ -0,0 +1,33 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2019 Laboratoire de Recherche et Développement de
+// l'Epita (LRDE)
+//
+// This file is part of Spot, a model checking library.
+//
+// Spot is free software; you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+//
+// Spot is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+// License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include <config.h>
+#include <spot/ltsmin/spins_interface.hh>
+#include <ltdl.h>
+
+namespace spot
+{
+    spins_interface::~spins_interface()
+    {
+      lt_dlhandle h = (lt_dlhandle) handle;
+      if (h)
+        lt_dlclose(h);
+      lt_dlexit();
+    }
+}
diff --git a/spot/ltsmin/spins_interface.hh b/spot/ltsmin/spins_interface.hh
index 0660f15f5..8983a8eea 100644
--- a/spot/ltsmin/spins_interface.hh
+++ b/spot/ltsmin/spins_interface.hh
@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2017 Laboratoire de Recherche et Développement de
+// Copyright (C) 2017, 2019 Laboratoire de Recherche et Développement de
 // l'Epita (LRDE)
 //
 // This file is part of Spot, a model checking library.
@@ -20,7 +20,6 @@
 #pragma once
 
 #include <memory>
-#include <ltdl.h>
 
 namespace spot
 {
@@ -52,13 +51,7 @@ namespace spot
     const char* (*get_type_name)(int type);
     int (*get_type_value_count)(int type);
     const char* (*get_type_value_name)(int type, int value);
-    ~spins_interface()
-    {
-      lt_dlhandle h = (lt_dlhandle) handle;
-      if (h)
-        lt_dlclose(h);
-      lt_dlexit();
-    }
+    ~spins_interface();
   };
 
   using spins_interface_ptr = std::shared_ptr<const spins_interface>;