diff --git a/evolution.spec b/evolution.spec
index cd93651..8cbe7d5 100644
--- a/evolution.spec
+++ b/evolution.spec
@@ -1,3 +1,5 @@
+%undefine __cmake_in_source_build
+
 %global _changelog_trimtime %(date +%s -d "1 year ago")
 %global _python_bytecompile_extra 0