vim-ctagser is a simple approach to handle ctags for system headers.
Install vim-ctagser, ensure you have ctags installed and run
:CtagsIndex. vim-ctagser will create a folder (~/.tags by default,
changeable by exporting $TAGSDIR) and instruct ctags to generate
tags for each system header in /usr/include and
/usr/local/include.
Headers in /usr/local/include take precedence over those in /usr/include.
vim-ctagser compares the modification times of a header and its corresponding tags file, ensuring that tags are only recreated for changed files.
Afterwards vim-ctagser will automatically add the appropriate tags-files
to your :h 'tags' upon opening or reloading a file.
If you want ctags files for your project use vim-gutentags, which does a good job at automatically updating your projects' tags files.