CLJS-2820 Compile cljs.loader regardless of whether :modules are used (#169)

Co-authored-by: Tom Connors <tvconnors@gmail.com>

Author: swannodette

src/main/clojure/cljs/closure.clj

@@ -1247,15 +1247,16 @@
   compiled last after all inputs. This is because all inputs must be known and
   they must already be sorted in dependency order."
   [inputs {:keys [modules] :as opts}]
-  (when-let [loader (when (seq modules)
-                      (->> inputs
-                           (filter
-                            (fn [input]
-                              (some '#{"cljs.loader" cljs.loader}
-                                    (:provides input))))
-                           first))]
-    (let [module-uris  (module-graph/modules->module-uris modules inputs opts)
-          module-infos (module-graph/modules->module-infos modules)]
+  (when-let [loader (->> inputs
+                         (filter
+                          (fn [input]
+                            (some '#{"cljs.loader" cljs.loader}
+                                  (:provides input))))
+                         first)]
+    (let [module-uris  (when (seq modules)
+                         (module-graph/modules->module-uris modules inputs opts))
+          module-infos (when (seq modules)
+                         (module-graph/modules->module-infos modules))]
       (swap! env/*compiler* ana/add-consts
              {'cljs.core/MODULE_INFOS
               (merge (const-expr-form @env/*compiler* 'cljs.core/MODULE_INFOS) module-infos)