Index: mapscript/python/CMakeLists.txt
===================================================================
--- mapscript/python/CMakeLists.txt.orig	2020-07-31 19:11:56.000000000 +0200
+++ mapscript/python/CMakeLists.txt	2020-09-05 14:44:10.142799065 +0200
@@ -146,7 +146,7 @@ install(
     endif()
 
     execute_process(
-      COMMAND ${PYTHON_EXECUTABLE} setup.py install \${PYTHON_ROOT} \${PYTHON_PREFIX}
+      COMMAND ${PYTHON_EXECUTABLE} setup.py install --install-lib=${PYTHON_SITE_PACKAGES} \${PYTHON_ROOT} \${PYTHON_PREFIX}
       WORKING_DIRECTORY ${OUTPUT_FOLDER}
     )
   "