diff --git a/armadillo.spec b/armadillo.spec
index be90003..bb4580f 100644
--- a/armadillo.spec
+++ b/armadillo.spec
@@ -13,6 +13,10 @@ Source:         http://sourceforge.net/projects/arma/files/%{name}-%{version}.ta
 %define old_epel 0
 %endif
 
+%if (0%{?rhel} || (0%{?fedora} && 0%{?fedora} < 33))
+%undefine __cmake_in_source_build
+%endif
+
 BuildRequires:  gcc-c++
 BuildRequires:  cmake, lapack-devel, arpack-devel
 %if %{old_epel} == 0