fix flymake tidy html error issue

2 description

os: ubuntu 16.04 desktop

emacs: GNU Emacs 24.5.1

The error info as below:

switched OFF Flymake mode for buffer emacs-default-keys.html due to fatal
status CFGERR, warning Configuration error has occurred while running
(tidy emacs-default-keys_flymake.html)

3 analysis

current installed tidy is too old. Replace it by using tidy-html5.

4 fix steps

$ git clone https://github.com/htacg/tidy-html5.git

$ sudo apt install xsltproc

$ cd build/cmake

$ cmake ../.. -DCMAKE_BUILD_TYPE=Release

$ make

$ sudo make install

After these operations, you can use flymake for html in emacs now.