From 07a003102948d5af2d8781bf4fe85d306d2ab448 Mon Sep 17 00:00:00 2001
From: Thomas Tuegel <ttuegel@gmail.com>
Date: Thu, 16 Apr 2015 10:09:28 -0500
Subject: [PATCH] melpaBuild: add unpackCmd for single-file packages

Emacs packages are commonly distributed as single .el files. This
unpackCmd handles them correctly and sets up sourceRoot. Other sources
are treated in the default manner.
---
 pkgs/build-support/emacs/generic.nix | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/pkgs/build-support/emacs/generic.nix b/pkgs/build-support/emacs/generic.nix
index 6fd630b13f4..d41f90ebd05 100644
--- a/pkgs/build-support/emacs/generic.nix
+++ b/pkgs/build-support/emacs/generic.nix
@@ -29,6 +29,19 @@ in
 stdenv.mkDerivation ({
   name = "emacs-${pname}${optionalString (version != null) "-${version}"}";
 
+  unpackCmd = ''
+    case "$curSrc" in
+      *.el)
+        cp $curSrc $pname.el
+        chmod +w $pname.el
+        sourceRoot="."
+        ;;
+      *)
+        _defaultUnpack "$curSrc"
+        ;;
+    esac
+  '';
+
   buildInputs = [emacs texinfo] ++ packageRequires ++ buildInputs;
   propagatedBuildInputs = packageRequires;
   propagatedUserEnvPkgs = packageRequires;