restart-emacs.patch

--- a/restart-emacs.el	1970-01-01 02:00:01.000000000 +0200
+++ b/restart-emacs.el	2021-06-13 14:37:50.520954543 +0300
@@ -94,12 +94,13 @@
   "Get absolute path to binary of currently running Emacs.
 
 On Windows get path to runemacs.exe if possible."
-  (let ((emacs-binary-path (expand-file-name invocation-name invocation-directory))
-        (runemacs-binary-path (when (memq system-type '(windows-nt ms-dos))
-                                (expand-file-name "runemacs.exe" invocation-directory))))
-    (if (and runemacs-binary-path (file-exists-p runemacs-binary-path))
-        runemacs-binary-path
-      emacs-binary-path)))
+  (if (getenv "NIX_DOOM_EMACS_BINARY") (getenv "NIX_DOOM_EMACS_BINARY")
+    (let ((emacs-binary-path (expand-file-name invocation-name invocation-directory))
+          (runemacs-binary-path (when (memq system-type '(windows-nt ms-dos))
+                                  (expand-file-name "runemacs.exe" invocation-directory))))
+      (if (and runemacs-binary-path (file-exists-p runemacs-binary-path))
+          runemacs-binary-path
+        emacs-binary-path))))
 
 (defun restart-emacs--record-tty-file (current &rest ignored)
   "Save the buffer which is being currently selected in the frame.