infra: add absoluteRuntime

# Conflicts:
#	babel.config.js

babel.config.js

@@ -11,6 +11,7 @@ module.exports = function(api) {
     exclude: ["transform-typeof-symbol"],
   };
   const envOpts = Object.assign({}, envOptsNoTargets);
+  let transformRuntimeOpts = null;
 
   let convertESM = true;
   let ignoreLib = true;
@@ -50,6 +51,17 @@ module.exports = function(api) {
       break;
   }
 
+  if (includeRuntime) {
+    const babelRuntimePackageJSONPath = require.resolve(
+      "@babel/runtime/package.json"
+    );
+    const path = require("path");
+    transformRuntimeOpts = {
+      version: require(babelRuntimePackageJSONPath).version,
+      absoluteRuntime: path.dirname(babelRuntimePackageJSONPath),
+    };
+  }
+
   const config = {
     // Our dependencies are all standard CommonJS, along with all sorts of
     // other random files in Babel's codebase, so we use script as the default,
@@ -123,7 +135,7 @@ module.exports = function(api) {
         ],
         plugins: [
           includeRuntime
-            ? ["@babel/transform-runtime", { version: "7.4.4" }]
+            ? ["@babel/transform-runtime", transformRuntimeOpts]
             : null,
         ].filter(Boolean),
       },