diff --git a/configure.ac b/configure.ac
index a4c800039..51f755f5f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -58,15 +58,16 @@ AC_PROG_YACC
 
 gl_INIT
 
-AC_LANG(C++)
 
 # Use -Werror since using -fvisibility under MinGW is only a warning.
 # (The option is ignored anyway since this does not make sense under windows).
-AC_SUBST([VISIBILITY_CXXFLAGS])
 AX_CHECK_COMPILE_FLAG([-Werror -fvisibility=hidden],
-  [VISIBILITY_CXXFLAGS="$VISIBILITY_CXXFLAGS -fvisibility=hidden -DSPOT_BUILD"
+  [CFLAGS="$CFLAGS -fvisibility=hidden"])
+AC_LANG(C++)
+AX_CHECK_COMPILE_FLAG([-Werror -fvisibility=hidden],
+  [CXXFLAGS="$CXXFLAGS -fvisibility=hidden"
   AX_CHECK_COMPILE_FLAG([-fvisibility-inlines-hidden],
-    [VISIBILITY_CXXFLAGS="$VISIBILITY_CXXFLAGS -fvisibility-inlines-hidden"])])
+    [CXXFLAGS="$CXXFLAGS -fvisibility-inlines-hidden -DSPOT_BUILD"])])
 
 AC_HEADER_UNORDERED_MAP
 AC_HEADER_TR1_UNORDERED_MAP
diff --git a/iface/dve2/dve2.hh b/iface/dve2/dve2.hh
index fa0745eb5..0fec5807b 100644
--- a/iface/dve2/dve2.hh
+++ b/iface/dve2/dve2.hh
@@ -1,4 +1,4 @@
-// Copyright (C) 2011 Laboratoire de Recherche et Developpement
+// Copyright (C) 2011, 2013 Laboratoire de Recherche et Developpement
 // de l'Epita (LRDE)
 //
 // This file is part of Spot, a model checking library.
@@ -55,12 +55,11 @@ namespace spot
   // \a dead an atomic proposition or constant to use for looping on
   //         dead states
   // \a verbose whether to output verbose messages
-  kripke* load_dve2(const std::string& file,
-		    bdd_dict* dict,
-		    const ltl::atomic_prop_set* to_observe,
-		    const ltl::formula* dead = ltl::constant::true_instance(),
-		    int compress = 0,
-		    bool verbose = true);
+  SPOT_API kripke*
+  load_dve2(const std::string& file, bdd_dict* dict,
+	    const ltl::atomic_prop_set* to_observe,
+	    const ltl::formula* dead = ltl::constant::true_instance(),
+	    int compress = 0, bool verbose = true);
 }
 
 #endif // SPOT_IFACE_DVE2_DVE2_HH
diff --git a/src/eltlparse/Makefile.am b/src/eltlparse/Makefile.am
index 1e38c9680..91f6bba7a 100644
--- a/src/eltlparse/Makefile.am
+++ b/src/eltlparse/Makefile.am
@@ -19,7 +19,7 @@
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I.. -DYY_NO_INPUT
 # Disable -Werror because too many versions of flex yield warnings.
-AM_CXXFLAGS = $(WARNING_CXXFLAGS:-Werror=) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS:-Werror=)
 
 eltlparsedir = $(pkgincludedir)/eltlparse
 
diff --git a/src/kripke/Makefile.am b/src/kripke/Makefile.am
index 3a10ef203..55c445d6f 100644
--- a/src/kripke/Makefile.am
+++ b/src/kripke/Makefile.am
@@ -18,7 +18,7 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I.. $(BUDDY_CPPFLAGS)
-AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
 
 kripkedir = $(pkgincludedir)/kripke
 
diff --git a/src/kripkeparse/Makefile.am b/src/kripkeparse/Makefile.am
index 2c6136827..8b5d531e7 100644
--- a/src/kripkeparse/Makefile.am
+++ b/src/kripkeparse/Makefile.am
@@ -18,7 +18,7 @@
 
 AM_CPPFLAGS = -I$(srcdir)/.. $(BUDDY_CPPFLAGS) -DYY_NO_INPUT
 # Disable -Werror because too many versions of flex yield warnings.
-AM_CXXFLAGS = $(WARNING_CXXFLAGS:-Werror=) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS:-Werror=)
 
 kripkeparsedir = $(pkgincludedir)/kripkeparse
 
diff --git a/src/ltlast/Makefile.am b/src/ltlast/Makefile.am
index b6917b026..e24430393 100644
--- a/src/ltlast/Makefile.am
+++ b/src/ltlast/Makefile.am
@@ -21,7 +21,7 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I..
-AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
 
 ltlastdir = $(pkgincludedir)/ltlast
 
diff --git a/src/ltlenv/Makefile.am b/src/ltlenv/Makefile.am
index 000484cc5..cba6c5cfc 100644
--- a/src/ltlenv/Makefile.am
+++ b/src/ltlenv/Makefile.am
@@ -1,5 +1,8 @@
-## Copyright (C) 2003, 2004, 2013  Laboratoire d'Informatique de Paris 6 (LIP6),
-## département Systèmes Répartis Coopératifs (SRC), Université Pierre
+## -*- coding: utf-8 -*-
+## Copyright (C) 2013 Laboratoire de Recherche et Développement de
+## l'Epita (LRDE).
+## Copyright (C) 2003, 2004  Laboratoire d'Informatique de Paris 6 (LIP6),
+## département Systèmes Répartis Coopératifs (SRC), Université Pierre
 ## et Marie Curie.
 ##
 ## This file is part of Spot, a model checking library.
@@ -18,7 +21,7 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 AM_CPPFLAGS = -I$(srcdir)/..
-AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
 
 ltlenvdir = $(pkgincludedir)/ltlenv
 
diff --git a/src/ltlparse/Makefile.am b/src/ltlparse/Makefile.am
index 498e7a4b4..ccbc0eac0 100644
--- a/src/ltlparse/Makefile.am
+++ b/src/ltlparse/Makefile.am
@@ -1,8 +1,9 @@
+## -*- coding: utf-8 -*-
 ## Copyright (C) 2008, 2009, 2010, 2011, 2012, 2013 Laboratoire de
-## Recherche et Développement de l'Epita (LRDE).
+## Recherche et Développement de l'Epita (LRDE).
 ## Copyright (C) 2003, 2004 Laboratoire d'Informatique de Paris
-## 6 (LIP6), département Systèmes Répartis Coopératifs (SRC),
-## Université Pierre et Marie Curie.
+## 6 (LIP6), département Systèmes Répartis Coopératifs (SRC),
+## Université Pierre et Marie Curie.
 ##
 ## This file is part of Spot, a model checking library.
 ##
@@ -21,7 +22,7 @@
 
 AM_CPPFLAGS = -I$(top_srcdir) -I$(srcdir)/.. -I.. -DYY_NO_INPUT
 # Disable -Werror because too many versions of flex yield warnings.
-AM_CXXFLAGS = $(WARNING_CXXFLAGS:-Werror=) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS:-Werror=)
 
 ltlparsedir = $(pkgincludedir)/ltlparse
 
diff --git a/src/ltlvisit/Makefile.am b/src/ltlvisit/Makefile.am
index 9c02257b1..a5572a827 100644
--- a/src/ltlvisit/Makefile.am
+++ b/src/ltlvisit/Makefile.am
@@ -1,9 +1,9 @@
 ## -*- coding: utf-8 -*-
 ## Copyright (C) 2010, 2011, 2012, 2013 Laboratoire de Recherche et
 ## Developpement de l'Epita (LRDE).
-## Copyright (C) 2004, 2005, 2006  Laboratoire d'Informatique de Paris 6 (LIP6),
-## département Systèmes Répartis Coopératifs (SRC), Université Pierre
-## et Marie Curie.
+## Copyright (C) 2004, 2005, 2006 Laboratoire d'Informatique de Paris
+## 6 (LIP6), département Systèmes Répartis Coopératifs (SRC),
+## Université Pierre et Marie Curie.
 ##
 ## This file is part of Spot, a model checking library.
 ##
@@ -21,7 +21,7 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I.. $(BUDDY_CPPFLAGS)
-AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
 
 ltlvisitdir = $(pkgincludedir)/ltlvisit
 
diff --git a/src/misc/Makefile.am b/src/misc/Makefile.am
index 999b2d2d9..45db2d663 100644
--- a/src/misc/Makefile.am
+++ b/src/misc/Makefile.am
@@ -21,7 +21,7 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I.. $(BUDDY_CPPFLAGS)
-AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
 
 miscdir = $(pkgincludedir)/misc
 
diff --git a/src/neverparse/Makefile.am b/src/neverparse/Makefile.am
index 1cd333c0e..904807c5e 100644
--- a/src/neverparse/Makefile.am
+++ b/src/neverparse/Makefile.am
@@ -19,7 +19,7 @@
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I.. $(BUDDY_CPPFLAGS) -DYY_NO_INPUT
 # Disable -Werror because too many versions of flex yield warnings.
-AM_CXXFLAGS = $(WARNING_CXXFLAGS:-Werror=) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS:-Werror=)
 
 neverparsedir = $(pkgincludedir)/neverparse
 
diff --git a/src/priv/Makefile.am b/src/priv/Makefile.am
index bb2bce145..9bcb75b4a 100644
--- a/src/priv/Makefile.am
+++ b/src/priv/Makefile.am
@@ -18,7 +18,7 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I.. $(BUDDY_CPPFLAGS)
-AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
 
 noinst_HEADERS = \
   acccompl.hh \
diff --git a/src/saba/Makefile.am b/src/saba/Makefile.am
index 5247c7b23..f5fd0c665 100644
--- a/src/saba/Makefile.am
+++ b/src/saba/Makefile.am
@@ -18,7 +18,7 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I.. $(BUDDY_CPPFLAGS)
-AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
 
 sabadir = $(pkgincludedir)/saba
 
diff --git a/src/sabaalgos/Makefile.am b/src/sabaalgos/Makefile.am
index 0e08129c1..44907efde 100644
--- a/src/sabaalgos/Makefile.am
+++ b/src/sabaalgos/Makefile.am
@@ -18,7 +18,7 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I.. $(BUDDY_CPPFLAGS)
-AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
 
 sabaalgosdir = $(pkgincludedir)/sabaalgos
 
diff --git a/src/ta/Makefile.am b/src/ta/Makefile.am
index ab2a121a3..92cf587fb 100644
--- a/src/ta/Makefile.am
+++ b/src/ta/Makefile.am
@@ -18,7 +18,7 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I.. $(BUDDY_CPPFLAGS)
-AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
 
 tadir = $(pkgincludedir)/ta
 
diff --git a/src/taalgos/Makefile.am b/src/taalgos/Makefile.am
index 750bcbc25..5b46df075 100644
--- a/src/taalgos/Makefile.am
+++ b/src/taalgos/Makefile.am
@@ -2,7 +2,7 @@
 ## Copyright (C) 2010, 2012, 2013 Laboratoire de Recherche et
 ## Développement de l'Epita (LRDE).
 ##
-## This file is part of Spot, a model checking library.et Marie Curie.
+## 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
@@ -19,7 +19,7 @@
 
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I.. $(BUDDY_CPPFLAGS)
-AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
 
 taalgosdir = $(pkgincludedir)/taalgos
 
diff --git a/src/tgba/Makefile.am b/src/tgba/Makefile.am
index a60ae67ad..8ec9fbfbc 100644
--- a/src/tgba/Makefile.am
+++ b/src/tgba/Makefile.am
@@ -21,7 +21,7 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I.. $(BUDDY_CPPFLAGS)
-AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
 
 tgbadir = $(pkgincludedir)/tgba
 
diff --git a/src/tgbaalgos/Makefile.am b/src/tgbaalgos/Makefile.am
index 297573568..dcbc871c7 100644
--- a/src/tgbaalgos/Makefile.am
+++ b/src/tgbaalgos/Makefile.am
@@ -23,7 +23,7 @@
 SUBDIRS = gtec
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I.. $(BUDDY_CPPFLAGS)
-AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
 
 tgbaalgosdir = $(pkgincludedir)/tgbaalgos
 
diff --git a/src/tgbaalgos/gtec/Makefile.am b/src/tgbaalgos/gtec/Makefile.am
index f8f108da7..4bd9dc403 100644
--- a/src/tgbaalgos/gtec/Makefile.am
+++ b/src/tgbaalgos/gtec/Makefile.am
@@ -21,7 +21,7 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 AM_CPPFLAGS = -I$(srcdir)/../.. -I../.. $(BUDDY_CPPFLAGS)
-AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
 
 gtecdir = $(pkgincludedir)/tgbaalgos/gtec
 
diff --git a/src/tgbaparse/Makefile.am b/src/tgbaparse/Makefile.am
index 164e795f7..eeb67ce86 100644
--- a/src/tgbaparse/Makefile.am
+++ b/src/tgbaparse/Makefile.am
@@ -22,7 +22,7 @@
 
 AM_CPPFLAGS = -I$(srcdir)/.. -I.. $(BUDDY_CPPFLAGS) -DYY_NO_INPUT
 # Disable -Werror because too many versions of flex yield warnings.
-AM_CXXFLAGS = $(WARNING_CXXFLAGS:-Werror=) $(VISIBILITY_CXXFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS:-Werror=)
 
 tgbaparsedir = $(pkgincludedir)/tgbaparse