diff --git a/ocaml-ocamlbuild.spec b/ocaml-ocamlbuild.spec
index e6781a5..2b67cbb 100644
--- a/ocaml-ocamlbuild.spec
+++ b/ocaml-ocamlbuild.spec
@@ -55,8 +55,13 @@ make configure \
 
 # Parallel builds fail.
 make \
+%ifarch %{ocaml_native_compiler}
      OCAMLC="ocamlc.opt -g" \
      OCAMLOPT="ocamlopt.opt -g"
+%else
+     OCAMLC="ocamlc -g" \
+     OCAMLOPT="ocamlopt -g"
+%endif
 
 
 %install