--- ./Makefile.in.orig
+++ ./Makefile.in
@@ -394,7 +394,7 @@
 	unbound.h
 libunbound/python/libunbound_wrap.c:	$(srcdir)/libunbound/python/libunbound.i unbound.h
 	@-if test ! -d libunbound/python; then $(INSTALL) -d libunbound/python; fi
-	$(SWIG) -python -o $@ $(CPPFLAGS) -DPY_MAJOR_VERSION=$(PY_MAJOR_VERSION) $(srcdir)/libunbound/python/libunbound.i
+	$(SWIG) -python -o $@ "$(CPPFLAGS)" -DPY_MAJOR_VERSION=$(PY_MAJOR_VERSION) $(srcdir)/libunbound/python/libunbound.i
 
 # Pyunbound python unbound wrapper
 _unbound.la:	libunbound_wrap.lo libunbound.la