diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6f674bd2d..1ccb2e9de 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -833,6 +833,7 @@ endif()
 # Detect availability of std::span
 ################################################################################
 unset(has_span CACHE)
+include(CheckCXXSourceCompiles)
 check_cxx_source_compiles("
     #include <span>
     int main()