--- graphviz-2.38.0.old/tclpkg/gv/Makefile.am	2014-04-13 21:40:25.000000000 +0100
+++ graphviz-2.38.0/tclpkg/gv/Makefile.am	2014-08-30 20:56:43.689541154 +0100
@@ -115,7 +115,7 @@
 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