Cannot be used with other ac-sources

[tkf]

auto-complete-clang-async recommends (setq ac-sources '(ac-source-clang-async)), but there are other useful sources (e.g., yasnippet) I want to use. I tried it with other sources, but AC does not show candidates from clang, for example when I insert foo.. Although it looks like that merging candidates from different sources is not possible due to limitation in AC (tkf/emacs-jedi#57), having multiple ac-sources is possible. Take a look at my emacs-jedi. It includes AC source for Python and I can use it with other AC sources.