Fix revealjs build for org +present

Noticed through upcoming test coverage improvements.

checks.nix

@@ -75,6 +75,8 @@ in {
   interactive = doomTest "minimal" { config = [ "default" ]; } { };
   interactive-without-loader = doomTest "minimal" { config = [ "default" ]; } { profileName = ""; };
 
+  org-re-reveal = doomTest "org-re-reveal" { lang = [ [ "org" "+present" ] ]; } { };
+
   # Various tests of module combinations.
   unpinned-org = doomTest "external-org" { app = [ [ "rss" "+org" ] ]; } { };
 }

elisp-packages.nix

@@ -18,6 +18,7 @@
   esuper,
   git,
   makeWrapper,
+  stdenvNoCC,
   writeText,
 }:
 {
@@ -185,6 +186,17 @@
       ./elisp-patches/helm-taskrunner-version.patch
     ];
   };
+  # reveal.js is not actually an ELisp package. Doom gets straight.el to install it,
+  # then makes org-re-reveal use it as data.
+  revealjs = stdenvNoCC.mkDerivation {
+    pname = "revealjs";
+    version = "9999snapshot";
+    buildPhase = ''
+      siteDir=$out/share/emacs/site-lisp/revealjs
+      mkdir -p $siteDir
+      cp -r css dist js plugin $siteDir/
+    '';
+  };
   # Make it byte-compile properly.
   code-review = esuper.code-review.overrideAttrs (attrs: {
     nativeBuildInputs = (attrs.nativeBuildInputs or [ ]) ++ [ git ];

tests.el

@@ -30,6 +30,13 @@
     (unless (string-search "/site-lisp/" path)
       (error "org-mode probably built-in: %s" path))))
 
+(defun test-org-re-reveal ()
+  "Test org-re-reveal can find reveal.js."
+  (require 'ox)
+  (require 'org-re-reveal)
+  (unless (string-search "/site-lisp/revealjs" org-re-reveal-root)
+    (error "org-re-reveal does not find our revealjs: %s" org-re-reveal-root)))
+
 (defun test-doom ()
   (let* ((out (getenv "out"))
          (test (intern-soft (format "test-%s" (getenv "testName"))))