emoji layer company-emoji font support

Font support for company-emoji on Linux or on Mac OS X and using the
Cocoa version of Emacs.
See https://github.com/dunn/company-emoji/blob/master/README.md

layers/+fun/emoji/README.org

@@ -23,6 +23,11 @@ To use this configuration layer, add it to your =~/.spacemacs=. You will need to
 add =emoji= to the existing =dotspacemacs-configuration-layers= list in this
 file.
 
+Linux user could install [[https://zhm.github.io/symbola/][Symbola]] font to get company-emoji support with =apt-get=
+
+#+BEGIN_SRC shell
+  apt-get install ttf-ancient-fonts
+#+END_SRC
 * Key bindings
 
 | Key Binding | Description                             |

layers/+fun/emoji/funcs.el

@@ -0,0 +1,29 @@
+;;; funcs.el --- Emoji Layer functions File for Spacemacs
+;;
+;; Copyright (c) 2012-2017 Sylvain Benner & Contributors
+;;
+;; Author: Sylvain Benner <sylvain.benner@gmail.com>
+;; URL: https://github.com/syl20bnr/spacemacs
+;;
+;; This file is not part of GNU Emacs.
+;;
+;;; License: GPLv3
+
+;; From https://github.com/dunn/company-emoji/README.md for Linux, or on
+;; Mac OS X and using the Cocoa version of Emacs
+(defun spacemacs//set-emoji-font (frame)
+  "Adjust the font settings of FRAME so Emacs can display emoji properly."
+  (cond
+   ((spacemacs/system-is-mac)
+    (set-fontset-font t 'symbol
+                      (font-spec :family "Apple Color Emoji")
+                      frame 'prepend))
+   ((spacemacs/system-is-linux)
+    (set-fontset-font t 'symbol
+                      (font-spec :family "Symbola")
+                      frame 'prepend))))
+
+(defun spacemacs//set-emoji-font-for-current-frame ()
+  "Adjust the font settings of current frame so Emacs can display emoji
+properly."
+  (spacemacs//set-emoji-font (selected-frame)))

layers/+fun/emoji/packages.el

@@ -39,4 +39,11 @@
 (defun emoji/init-company-emoji ()
   (use-package company-emoji
     :defer t
-    :init (setq company-emoji-insert-unicode nil)))
+    :init
+    (progn
+      (setq company-emoji-insert-unicode nil)
+      ;; For when Emacs is started in GUI mode:
+      (spacemacs//set-emoji-font nil)
+      ;; Hook for when a frame is created with emacsclient
+      (spacemacs|do-after-display-system-init
+       (spacemacs//set-emoji-font-for-current-frame)))))