diff --git a/libsndfile.spec b/libsndfile.spec
index 20824a7..23573ae 100644
--- a/libsndfile.spec
+++ b/libsndfile.spec
@@ -83,7 +83,7 @@ rm -rf $RPM_BUILD_ROOT%{_docdir}/libsndfile1-dev
 find %{buildroot} -type f -name "*.la" -delete
 
 # fix multilib issues
-%if %{?__isa_bits} == 64
+%ifarch aarch64 %{power64} s390x x86_64
 %define wordsize 64
 %else
 %define wordsize 32