Without --no-build-isolation "pip install" attempts to reinstall setuptools from pypi
--- a/cmake/virtualenv.cmake
+++ b/cmake/virtualenv.cmake
@@ -28,7 +28,7 @@ endfunction()
 function(virtualenv_install)
     virtualenv_create()
     execute_process(
-      COMMAND ${VIRTUALENV_BIN_DIR}/${VIRTUALENV_PYTHON_EXENAME} -m pip install ${ARGN}
+      COMMAND ${VIRTUALENV_BIN_DIR}/${VIRTUALENV_PYTHON_EXENAME} -m pip install --no-build-isolation ${ARGN}
       COMMAND_ECHO STDOUT
       RESULT_VARIABLE return_code
       ERROR_VARIABLE error_message