diff --git a/Makefile b/Makefile
index 5502515..8a8caf1 100644
--- a/Makefile
+++ b/Makefile
@@ -5,18 +5,26 @@ LIBHDT=$(HDTHOME)/libhdt
 LIBCDS=$(HDTHOME)/libcds
 HDTLIB=$(LIBHDT)/.libs
 CDSLIB=$(LIBCDS)/.libs
-SOBJ=	$(PACKSODIR)/hdt4pl.$(SOEXT)
+SOBJ=	$(SWIPL_MODULE_DIR)/hdt4pl.$(SWIPL_MODULE_EXT)
 NPROC:=$(shell expr $$(nproc) + 1)
 MAKE_J=-j$(NPROC)
-CFLAGS+=-I$(LIBHDT)/include -g
+CFLAGS=$(SWIPL_CFLAGS) -I$(LIBHDT)/include -g
 # This doesn't work because the *.so files get picked first:
 #     LIBS=	-L$(HDTLIB) -L$(CDSLIB) -lhdt -lcds
-# Instead, we copy the *.a files intothe same directory as $(OBJ)
+# Instead, we copy the *.a files into the same directory as $(OBJ)
 # - see the rules for $(OBJ2).
 LIBS= -Lc -lhdt -lcds
 OBJ=	c/hdt4pl.o
 OBJ2=	c/libcds.a c/libhdt.a
-LD=g++
+# WARNING: A previous version of this Makefile set LD=g++
+#          ... this confuses hdt-cpp's use of libtool.
+#          The correct way of using the linker is with $(CC):
+#          see the "implicit variables" in the GNU make documentation
+#          Note that pack_version(2) defines `SWIPL_CC` and
+#          "swipl pack install ." creates ./buildenv.sh, which
+#          defines the SWIPL_* environment variables
+
+CC=$(SWIPL_CC)
 
 all:	$(SOBJ)
 
@@ -27,8 +35,8 @@ c/libcds.a: $(CDSLIB)/libcds.a
 	ln -f $< $@
 
 $(SOBJ): $(OBJ) $(OBJ2)
-	mkdir -p $(PACKSODIR)
-	$(LD) $(ARCH) $(LDSOFLAGS) -o $@ $< $(LIBS) $(SWISOLIB) -lserd-0
+	mkdir -p $(SWIPL_MODULE_DIR)
+	$(CC) $(ARCH) $(SWIPL_MODULE_LDFLAGS) -o $@ $< $(LIBS) $(SWIPL_MODULE_LIB) -lserd-0
 
 c/hdt4pl.o: c/hdt4pl.cpp $(HDTLIB)/libhdt.a $(CDSLIB)/libcds.a
 	$(CC) $(ARCH) $(CFLAGS) -c -o $@ c/hdt4pl.cpp
@@ -38,6 +46,9 @@ $(HDTLIB)/libhdt.a $(HDTLIB)/libcds.a: FORCE
 
 FORCE:
 
+check::
+	$(MAKE) -C $(HDTHOME) $(MAKE_J) check
+
 check::
 	$(SWIPL) -g test_hdt -t halt test/test_hdt.pl
 
@@ -51,3 +62,4 @@ clean:
 distclean: clean
 	rm -f $(SOBJ)
 	[ ! -f $(HDTHOME)/Makefile ] || $(MAKE) -C $(HDTHOME) distclean
+	cd $(HDTHOME) && git clean -d -f -x
diff --git a/pack.pl b/pack.pl
index f8a62f4..7abca1e 100644
--- a/pack.pl
+++ b/pack.pl
@@ -1,6 +1,7 @@
 name(hdt).
-version('0.5.3').
-% TODO: swipl_version([90121]).
+version('0.5.4').
+pack_version(2).
+% swipl_version([90302]). % TODO: add stable version
 title('Access RDF HDT files').
 keywords(['RDF']).
 author( 'Jan Wielemaker', 'J.Wielemaker@vu.nl' ).