diff --git a/doxygen.spec b/doxygen.spec
index 9b63ce1..161085b 100644
--- a/doxygen.spec
+++ b/doxygen.spec
@@ -173,7 +173,7 @@ make tests -C %{BuildDir}
 %doc LANGUAGE.HOWTO README.md
 %license LICENSE
 %if ! 0%{?_module_build}
-%if %{xapian_core_support} == "ON"
+%if "x%{?xapian_core_support}" == "xON"
 %{_bindir}/doxyindexer
 %{_bindir}/doxysearch*
 %endif