diff --git a/build/cmake/init.cmake b/build/cmake/init.cmake
index d9b78ba412..6dca1cc869 100644
--- a/build/cmake/init.cmake
+++ b/build/cmake/init.cmake
@@ -317,6 +317,7 @@ if (wxUSE_WEBREQUEST)
         endif()
     endif()
 
+    include(CheckCSourceCompiles)
     if(wxUSE_WEBREQUEST_WINHTTP)
         check_c_source_compiles("#include <windows.h>
                                  #include <winhttp.h>