diff --git a/macros.cmake b/macros.cmake
index 7692f4d..afb8858 100644
--- a/macros.cmake
+++ b/macros.cmake
@@ -7,6 +7,7 @@
 %_cmake_version @@CMAKE_VERSION@@
 %__cmake /usr/bin/cmake
 %__ctest /usr/bin/ctest
+%__cmake_in_source_build 1
 %__cmake_builddir %{!?__cmake_in_source_build:"%{_vpath_builddir}"}%{?__cmake_in_source_build:"."}
 
 # - Set default compile flags