Fix MY_INSTALL_PREFIX

ext/CMakeLists.txt

@@ -35,15 +35,18 @@ IF(BUILD_PYTHON_INTERFACE)
  if(CALL_FROM_SETUP_PY)
  # The CMakeExtension will set CMAKE_INSTALL_PREFIX to the root
  # of the resulting wheel archive
+ MESSAGE(STATUS "MY_INSTALL_PREFIX: CMAKE_INSTALL_PREFIX")
  SET(MODULE_NAME ${PROJECT_NAME})
  SET(MY_INSTALL_PREFIX ${CMAKE_INSTALL_PREFIX})
  else()
  # The Python package is installed directly in the folder of the
  # detected interpreter (system, user, or virtualenv)
+ MESSAGE(STATUS "MY_INSTALL_PREFIX: Python3_SITELIB")
  set(MY_INSTALL_PREFIX ${Python3_SITELIB})
  endif()
  # Did not find installation prefix library location of python
  if(NOT MY_INSTALL_PREFIX)
+ MESSAGE(STATUS "MY_INSTALL_PREFIX: sysconfig.get_path('platlib')")
  execute_process(COMMAND ${Python3_EXECUTABLE} -c "import sysconfig; print(sysconfig.get_path('platlib'))"
  WORKING_DIRECTORY ${PROJECT_BINARY_DIR}
  OUTPUT_VARIABLE MY_INSTALL_PREFIX