[buddy] Restrict the number of exported symbols.

* src/bdd.h, src/bvec.h, src/fdd.h: Declare all exported
symbols using BUDDY_API, a new macro that sets visibility=default.
* src/Makefile.am: Compile with -fvisibility=hidden by default,
and compile the C++ part with -fvisibility-inlines-hidden as well.

buddy/src/Makefile.am

@@ -1,17 +1,29 @@
-# For
-AM_CPPFLAGS = -I$(top_builddir) -DVERSION=23
 
 include_HEADERS = bdd.h fdd.h bvec.h
 
+BUDDY_FLAGS = -I$(top_builddir) -DVERSION=23 \
+  -fvisibility=hidden -DBUDDY_DLL_EXPORTS -DBUDDY_DLL
+
+# Compile the C++ part of the library with
+# -fvisibility-inlines-hidden, this option is not valid for C.
 lib_LTLIBRARIES = libbdd.la
-libbdd_la_SOURCES = \
+libbdd_la_CPPFLAGS = $(BUDDY_FLAGS) -fvisibility-inlines-hidden
+libbdd_la_SOURCES = cppext.cxx
+libbdd_la_LIBADD = libbdd_c.la
+# See the `Updating version info' node of the Libtool manual before
+# changing this.
+libbdd_la_LDFLAGS = -no-undefined -version-info 0:0:0
+
+# The C part of the library.
+noinst_LTLIBRARIES = libbdd_c.la
+libbdd_c_la_CPPFLAGS = $(BUDDY_FLAGS)
+libbdd_c_la_SOURCES = \
  bddio.c \
  bddop.c \
  bddtree.h \
  bvec.c \
  cache.c \
  cache.h \
- cppext.cxx \
  fdd.c \
  imatrix.c \
  imatrix.h \
@@ -23,10 +35,7 @@ libbdd_la_SOURCES = \
  reorder.c \
  tree.c
 
-# See the `Updating version info' node of the Libtool manual before
-# changing this.
-libbdd_la_LDFLAGS = -no-undefined -version-info 0:0:0
-
 check_PROGRAMS = bddtest
 bddtest_SOURCES = bddtest.cxx
+bddtest_CPPFLAGS = -I$(top_builddir)
 bddtest_LDADD = ./libbdd.la