gnu: Add Node LTS.

* gnu/packages/node.scm (node)[arguments]: Adjust 'patch-files' phase to
ignore missing files.
(node-lts): New public variable.

gnu/packages/node.scm

@@ -5,6 +5,7 @@
 ;;; Copyright © 2016 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2017 Mike Gerwitz <mtg@gnu.org>
 ;;; Copyright © 2018 Tobias Geerinckx-Rice <me@tobias.gr>
+;;; Copyright © 2018 Marius Bakke <mbakke@fastmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -86,6 +87,14 @@
        (modify-phases %standard-phases
          (add-before 'configure 'patch-files
            (lambda* (#:key inputs #:allow-other-keys)
+
+             ;; This phase is inherited by Node LTS, which does not have all
+             ;; the files listed here.  Use this helper for convenience.
+             (define (delete-if-exists file)
+               (if (file-exists? file)
+                   (delete-file file)
+                   '()))
+
              ;; Fix hardcoded /bin/sh references.
              (substitute* '("lib/child_process.js"
                             "lib/internal/v8_prof_polyfill.js"
@@ -103,7 +112,7 @@
 
              ;; FIXME: These tests depend on being able to install eslint.
              ;; See https://github.com/nodejs/node/issues/17098.
-             (for-each delete-file
+             (for-each delete-if-exists
                        '("test/parallel/test-eslint-alphabetize-errors.js"
                          "test/parallel/test-eslint-buffer-constructor.js"
                          "test/parallel/test-eslint-documented-errors.js"
@@ -111,7 +120,7 @@
 
              ;; FIXME: These tests fail in the build container, but they don't
              ;; seem to be indicative of real problems in practice.
-             (for-each delete-file
+             (for-each delete-if-exists
                        '("test/async-hooks/test-ttywrap.readstream.js"
                          "test/parallel/test-util-inspect.js"
                          "test/parallel/test-v8-serdes.js"
@@ -130,7 +139,7 @@
              ;; TLS certificates that are bundled with the source.  We want this
              ;; package to be reproducible forever, so remove those.
              ;; TODO: Regenerate certs instead.
-             (for-each delete-file
+             (for-each delete-if-exists
                        '("test/parallel/test-tls-passphrase.js"
                          "test/parallel/test-tls-server-verify.js"))
              #t))
@@ -188,3 +197,16 @@ devices.")
     (home-page "https://nodejs.org/")
     (license expat)
     (properties '((timeout . 3600))))) ; 1 h
+
+(define-public node-lts
+  (package
+    (inherit node)
+    (name "node-lts")
+    (version "8.12.0")
+    (source (origin
+              (inherit (package-source node))
+              (uri (string-append "https://nodejs.org/dist/v" version
+                                  "/node-v" version ".tar.xz"))
+              (sha256
+               (base32
+                "16j1rrxkhmvpcw689ndw1raql1gz4jqn7n82z55zn63c05cgz7as"))))))