diff --git a/rpm/SPECS/openmodelica.spec.tpl b/rpm/SPECS/openmodelica.spec.tpl
index cbdc7c0..1174f43 100644
--- a/rpm/SPECS/openmodelica.spec.tpl
+++ b/rpm/SPECS/openmodelica.spec.tpl
@@ -187,6 +187,7 @@ source /opt/rh/devtoolset-11/enable
 source /opt/rh/gcc-toolset-11/enable
 %endif
 
+export LANG=C.UTF-8
 autoreconf --install
 ./configure CFLAGS="-Os" CXXFLAGS="-Os" QTDIR=/usr/%{_lib}/{omqtversion} %{withomniorb} %{withqt6} CONFIGUREFLAGS %{?devtoolsconfigureflags} --without-omc --prefix=/opt/%{name} --without-omlibrary %{cmakecommand}