diff --git a/ocaml-gsl.spec b/ocaml-gsl.spec
index 198477d..42b2704 100644
--- a/ocaml-gsl.spec
+++ b/ocaml-gsl.spec
@@ -1,8 +1,6 @@
-%global opt %(test -x %{_bindir}/ocamlopt && echo 1 || echo 0)
-
 Name:           ocaml-gsl
 Version:        1.19.1
-Release:        9%{?dist}
+Release:        10%{?dist}
 Summary:        Interface to GSL (GNU scientific library) for OCaml
 License:        GPLv2
 
@@ -62,7 +60,7 @@ make install
 %files
 %doc COPYING.txt
 %{_libdir}/ocaml/gsl
-%if %opt
+%ifarch %{ocaml_native_compiler}
 %exclude %{_libdir}/ocaml/gsl/*.a
 %exclude %{_libdir}/ocaml/gsl/*.cmxs
 %exclude %{_libdir}/ocaml/gsl/*.cmxa
@@ -74,7 +72,7 @@ make install
 
 %files devel
 %doc COPYING.txt AUTHORS.txt CHANGES.txt README.md NOTES.md
-%if %opt
+%ifarch %{ocaml_native_compiler}
 %{_libdir}/ocaml/gsl/*.a
 %{_libdir}/ocaml/gsl/*.cmxs
 %{_libdir}/ocaml/gsl/*.cmxa
@@ -83,8 +81,9 @@ make install
 
 
 %changelog
-* Tue Aug 08 2017 Richard W.M. Jones <rjones@redhat.com> - 1.19.1-9
+* Tue Aug 08 2017 Richard W.M. Jones <rjones@redhat.com> - 1.19.1-10
 - OCaml 4.05.0 rebuild.
+- Use ocaml_native_compiler macro instead of opt test.
 
 * Thu Aug 03 2017 Fedora Release Engineering <releng@fedoraproject.org> - 1.19.1-8
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_27_Binutils_Mass_Rebuild