diff --git a/cmake/DD4hepBuild.cmake b/cmake/DD4hepBuild.cmake
index c1b8c2c31ce4420077f457319f5b9da371a3e258..0b1ff6a3936863b214464a40ab60b282f1691bee 100644
--- a/cmake/DD4hepBuild.cmake
+++ b/cmake/DD4hepBuild.cmake
@@ -33,6 +33,7 @@ endmacro(dd4hep_to_parent_scope)
 #
 #---------------------------------------------------------------------------------------------------
 macro(dd4hep_set_compiler_flags)
+  include(CheckCXXCompilerFlag)
   CHECK_CXX_COMPILER_FLAG("-std=c++14" FLAG_CXX14)
   CHECK_CXX_COMPILER_FLAG("-std=c++11" FLAG_CXX11)
   CHECK_CXX_COMPILER_FLAG("-ftls-model=global-dynamic" FLAG_FTLS)