diff --git a/ghc.spec b/ghc.spec
index 4eb1df7..66df949 100644
--- a/ghc.spec
+++ b/ghc.spec
@@ -580,9 +580,9 @@ cd hadrian
 %endif
 %define hadrian_docs %{!?with_haddock:--docs=no-haddocks} %{!?with_manual:--docs=no-sphinx}%{?with_manual:--docs=no-sphinx-pdfs}
 # quickest does not build shared libs
-%{hadrian} %{?_smp_mflags} --flavour=%{!?with_prodbuild:quick+no_profiled_libs}%{?with_prodbuild:perf%{!?with_ghc_prof:+no_profiled_libs}}%{?hadrian_llvm} %{hadrian_docs} binary-dist-dir
+%{hadrian} -j1 --flavour=%{!?with_prodbuild:quick+no_profiled_libs}%{?with_prodbuild:perf%{!?with_ghc_prof:+no_profiled_libs}}%{?hadrian_llvm} %{hadrian_docs} binary-dist-dir
 %else
-make %{?_smp_mflags}
+make -j1
 %endif