diff --git a/package/package.json b/package/package.json
index e9bc8208d7..6101038245 100644
--- a/package/package.json
+++ b/package/package.json
@@ -3,5 +3,11 @@
   "version": "3.20.0-beta.1",
   "description": "OpenLayers",
   "main": "index.js",
-  "license": "BSD-2-Clause"
+  "license": "BSD-2-Clause",
+  "dependencies": {
+    "pbf": "3.0.5",
+    "pixelworks": "1.1.0",
+    "rbush": "2.0.1",
+    "vector-tile": "1.3.0"
+  }
 }
diff --git a/transforms/common.js b/transforms/common.js
index 5cc4dab91d..8935e21c9b 100644
--- a/transforms/common.js
+++ b/transforms/common.js
@@ -1,3 +1,5 @@
+var pkg = require('../package.json');
+
 function rename(name) {
   const parts = name.split('.');
   return `_${parts.join('_')}_`;
@@ -6,6 +8,24 @@ function rename(name) {
 function resolve(fromName, toName) {
   const fromParts = fromName.split('.');
   const toParts = toName.split('.');
+  if (toParts[0] === 'ol' && toParts[1] === 'ext') {
+    let name = toParts[2];
+    let packageName;
+    for (let i = 0, ii = pkg.ext.length; i < ii; ++i) {
+      const dependency = pkg.ext[i];
+      if (dependency.module === name) {
+        packageName = name;
+        break;
+      } else if (dependency.name === name) {
+        packageName = dependency.module;
+        break;
+      }
+    }
+    if (!packageName) {
+      throw new Error(`Can't find package name for ${toName}`);
+    }
+    return packageName;
+  }
   var commonDepth = 1;
   var fromLength = fromParts.length;
   while (commonDepth < fromLength - 1) {