--- graphviz-2.30.1.old/tclpkg/gv/Makefile.am	2013-02-14 13:27:39.000000000 +0000
+++ graphviz-2.30.1/tclpkg/gv/Makefile.am	2017-09-16 12:12:11.571092950 +0100
@@ -109,7 +109,7 @@
 libgv_ocaml_la_SOURCES = $(BASESOURCES) gv_dummy_init.c
 libgv_ocaml_la_LIBADD = $(BASELIBS) $(OCAML_LIBS)
 libgv_ocaml_la_LDFLAGS = -module -avoid-version
-libgv_ocaml_la_CPPFLAGS = $(BASECPPFLAGS) $(OCAML_INCLUDES)
+libgv_ocaml_la_CPPFLAGS = $(BASECPPFLAGS) $(OCAML_INCLUDES) -Dint64=int64_t
 gv.ml gv.mli: gv_ocaml.cpp
 gv_ocaml.cpp: gv.i
 	$(SWIG) -c++ -ocaml -o gv_ocaml.cpp $(srcdir)/gv.i