wraps gtags-find-tag to use imenu if it looks like a better idea

gtags-wrapper.el

(defun gtags-wrap-find-tag ()
  "Just a simple wrapper for gtags-find-tag. This is needed for
ubiquitous exceptions, but it also tries to use imenu before
actually trying to use gtags. This way if we have a single file
project we do not need gtags to jump around. Also we dont need to
regenerate gtags for local symbols."

  (interactive)
  (let* ((current-token (gtags-current-token))
   (imenu-tokens (mapcar (lambda (x) (car x)) (imenu--make-index-alist)))
	 (use-imenu (member current-token imenu-tokens)))
    (if use-imenu
	(progn (gtags-push-context) (call-interactively 'imenu))
      (progn
	(when (null (gtags-get-rootpath))
	  (gtags-generate-gtags))
	(widen) (gtags-find-tag)))))