diff --git a/third-party/cmake/PythonSetup.cmake b/third-party/cmake/PythonSetup.cmake
index 9042eaec3..3298dbd00 100644
--- a/third-party/cmake/PythonSetup.cmake
+++ b/third-party/cmake/PythonSetup.cmake
@@ -206,10 +206,10 @@ ELSE(INSTALL_ROOT)
 ENDIF(INSTALL_ROOT)
 
 EXECUTE_PROCESS(
-  COMMAND ${PYTHON_EXECUTABLE}
-    ${SETUP_PY}
+  COMMAND "${PYTHON_EXECUTABLE}"
+    "${SETUP_PY}"
     install
     --prefix=${PREFIX}
     ${INSTALL_ROOT_ARGS}
     ${EXTRA_ARGS}
-  WORKING_DIRECTORY ${WDIR})
+  WORKING_DIRECTORY "${WDIR}")