Fix missing 'define-fringe-bitmap' function errors

If Emacs wasn't built with X, Cocoa or NS display support (as is the
case for evm emacs-25.1-travis build), the fringe library is missing and
throws errors.

core/core-ui.el

@@ -218,7 +218,9 @@ file."
   :init (add-hook 'lisp-mode-hook #'rainbow-delimiters-mode))
 
 ;; indicators for empty lines past EOF
-(def-package! vi-tilde-fringe :demand t
+(def-package! vi-tilde-fringe
+  :when (display-graphic-p)
+  :demand t
   :config (global-vi-tilde-fringe-mode t))
 
 ;; For a distractions-free-like UI, that dynamically resizes margets and can

modules/feature/syntax-checker/config.el

@@ -22,8 +22,9 @@
         :n "k"   #'flycheck-error-list-previous-error
         :n "RET" #'flycheck-error-list-goto-error)
 
+  (when (fboundp 'define-fringe-bitmap)
     (define-fringe-bitmap 'flycheck-fringe-bitmap-double-arrow
-    [0 0 0 0 0 4 12 28 60 124 252 124 60 28 12 4 0 0 0 0])
+      [0 0 0 0 0 4 12 28 60 124 252 124 60 28 12 4 0 0 0 0]))
 
   (after! evil
     ;; Flycheck buffer on ESC in normal mode.

modules/ui/doom/config.el

@@ -124,6 +124,7 @@
 
 
 ;; subtle diff indicators in the fringe
+(when (display-graphic-p)
   (after! git-gutter-fringe
     ;; places the git gutter outside the margins.
     (setq-default fringes-outside-margins t)
@@ -136,4 +137,4 @@
       "X......."
       "XX......"
       "XXX....."
-    "XXXX...."))
+      "XXXX....")))