Flycheck中预编译条件如何设置

我查到可能设置flycheck-clang-definitions

如果我需要-DPSV和-DSH的话,那么在.dir-locals.el中如何写?

c++-mode 为例,M-x add-dir-local-variable RET c+±mode RET flycheck-clang-definitions RET ("-DPSV" “-DSH”) RET 产生:

;;; Directory Local Variables
;;; For more information see (info "(emacs) Directory Variables")

((c++-mode
  (flycheck-clang-definitions "-DPSV" "-DSH")))