[api-minor] Tweak the Node.js fake worker loader to prevent `Critical…

… dependency: ...` warnings from Webpack

Since bundlers, such as Webpack, cannot be told to leave `require` statements alone we are thus forced to jump through hoops in order to prevent these warnings in third-party deployments of the PDF.js library; please see [Webpack issue 8826](https://github.com/webpack/webpack) and libraries such as [require-fool-webpack](https://github.com/sindresorhus/require-fool-webpack).

*Please note:* This is based on the assumption that code running in Node.js won't ever be affected by e.g. Content Security Policies that prevent use of `eval`. If that ever occurs, we should revert to a normal `require` statement and simply document the Webpack warnings instead.

src/display/api.js

@@ -12,7 +12,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-/* globals __non_webpack_require__ */
 /* eslint no-var: error */
 
 /**
@@ -1471,6 +1470,7 @@ const PDFWorker = (function PDFWorkerClosure() {
   let fakeWorkerCapability;
 
   if (typeof PDFJSDev !== 'undefined' && PDFJSDev.test('GENERIC')) {
+    // eslint-disable-next-line no-undef
     if (isNodeJS && typeof __non_webpack_require__ === 'function') {
       // Workers aren't supported in Node.js, force-disabling them there.
       isWorkerDisabled = true;
@@ -1534,8 +1534,22 @@ const PDFWorker = (function PDFWorkerClosure() {
         return worker.WorkerMessageHandler;
       }
       if ((typeof PDFJSDev !== 'undefined' && PDFJSDev.test('GENERIC')) &&
+          // eslint-disable-next-line no-undef
           (isNodeJS && typeof __non_webpack_require__ === 'function')) {
-        const worker = __non_webpack_require__(getWorkerSrc());
+        // Since bundlers, such as Webpack, cannot be told to leave `require`
+        // statements alone we are thus forced to jump through hoops in order
+        // to prevent `Critical dependency: ...` warnings in third-party
+        // deployments of the built `pdf.js`/`pdf.worker.js` files; see
+        // https://github.com/webpack/webpack/issues/8826
+        //
+        // The following hack is based on the assumption that code running in
+        // Node.js won't ever be affected by e.g. Content Security Policies that
+        // prevent the use of `eval`. If that ever occurs, we should revert this
+        // to a normal `__non_webpack_require__` statement and simply document
+        // the Webpack warnings instead (telling users to ignore them).
+        //
+        // eslint-disable-next-line no-eval
+        const worker = eval('require')(getWorkerSrc());
         return worker.WorkerMessageHandler;
       }
       await loadScript(getWorkerSrc());