diff --git a/libkolabxml.spec b/libkolabxml.spec
index d702307..ac26975 100644
--- a/libkolabxml.spec
+++ b/libkolabxml.spec
@@ -1,4 +1,6 @@
 
+%undefine __cmake_in_source_build
+
 %{?!mono_arches: %global mono_arches %{ix86} x86_64 sparc sparcv9 ia64 %{arm} alpha s390x ppc ppc64}
 
 %ifarch %{mono_arches}