diff --git a/resize/Makefile.am b/resize/Makefile.am
index 31fd71b7a..7d4cade57 100644
--- a/resize/Makefile.am
+++ b/resize/Makefile.am
@@ -56,7 +56,7 @@ bin_SCRIPTS = virt-resize
 # -I $(top_builddir)/src/.libs is a hack which forces corresponding -L
 # option to be passed to gcc, so we don't try linking against an
 # installed copy of libguestfs.
-OCAMLPACKAGES = -package str -I $(top_builddir)/src/.libs -I ../ocaml
+OCAMLPACKAGES = -package str,unix -I $(top_builddir)/src/.libs -I ../ocaml
 if HAVE_OCAML_PKG_GETTEXT
 OCAMLPACKAGES += -package gettext-stub
 endif