Seeing this issue by chance.
You can get irony support with the following code:
(defun company-c-headers-path-user-irony ()
"Return the user include paths for the current buffer."
(when irony-mode
(irony--extract-user-search-paths irony--compile-options
irony--working-directory)))
(setq company-c-headers-path-user #'company-c-headers-path-user-irony)
Seeing this issue by chance. You can get irony support with the following code: