+*** flycheck
+#+BEGIN_SRC emacs-lisp :tangle yes :results silent
+ (use-package flycheck
+ :ensure t)
+#+END_SRC
+*** irony
+#+BEGIN_SRC emacs-lisp :tangle yes :results silent
+ (use-package irony
+ :ensure t
+ :config
+ (add-hook 'c++-mode-hook 'irony-mode)
+ (add-hook 'c-mode-hook 'irony-mode)
+ (add-hook 'objc-mode-hook 'irony-mode))
+#+END_SRC
+
+Install clang, on mac, it has =libclang.dylib=, but no develop headers. Install by =brew=
+#+BEGIN_SRC sh
+ brew install llvm --with-clang
+#+END_SRC
+
+then install irony searver, and =LIBCLANG_LIBRARY= and =LIBCLANG_INCLUDE_DIR= accordingly
+#+BEGIN_SRC emacs-lisp :tangle yes :results silent
+ (irony-install-server)
+#+END_SRC
+
+#+BEGIN_SRC sh
+ cmake -DLIBCLANG_LIBRARY\=/usr/local/Cellar/llvm/3.6.2/lib/libclang.dylib \
+ -DLIBCLANG_INCLUDE_DIR=/usr/local/Cellar/llvm/3.6.2/include \
+ -DCMAKE_INSTALL_PREFIX\=/Users/peli3/.emacs.d/irony/ \
+ /Users/peli3/.emacs.d/elpa/irony-20160713.1245/server && cmake --build . --use-stderr --config Release --target install
+#+END_SRC
+
+*** yasnippet
+#+BEGIN_SRC emacs-lisp :tangle yes :results silent
+ (use-package yasnippet
+ :ensure t)
+#+END_SRC
+