Add xelb non-posix shell patch

0001-Fix-startup-using-non-posix-shells.patch

@@ -0,0 +1,30 @@
+From 407cce8dd8b0e621449c6c3015c303539f53819b Mon Sep 17 00:00:00 2001
+From: adisbladis <adisbladis@gmail.com>
+Date: Fri, 28 Dec 2018 16:54:34 +0000
+Subject: [PATCH] Fix startup using non-posix shells
+
+* xcb.el (xcb:create-auth-info): Use lisp for string substitution instead of shell
+---
+ xcb.el | 6 +++++-
+ 1 file changed, 5 insertions(+), 1 deletion(-)
+
+diff --git a/xcb.el b/xcb.el
+index 7ed2d3e..a769d2f 100644
+--- a/xcb.el
++++ b/xcb.el
+@@ -147,7 +147,11 @@
+ (defun xcb:create-auth-info ()
+   "Create the default `auth-info'."
+   (let ((xauth-output (shell-command-to-string
+-                       "xauth list ${DISPLAY#localhost} 2>/dev/null"))
++                       (concat
++                        "xauth list "
++                        (replace-regexp-in-string "^localhost" ""
++                                                  (getenv "DISPLAY"))
++                        " 2>/dev/null")))
+         (name "MIT-MAGIC-COOKIE-1") ;only support MIT-MAGIC-COOKIE-1 protocol.
+         (data ""))
+     (if (string= "" xauth-output)
+-- 
+2.19.2
+

default.nix

@@ -33,6 +33,8 @@ in {
         packageRequires = [ cl-generic super.emacs ];
 
         src = mkSrc "xelb";
+
+        patches = [ ./0001-Fix-startup-using-non-posix-shells.patch ];
       };
     in {
       exwm = melpaBuild {