Don't add "use strict" to external libraries

inst/www/shared/selectize/accessibility/js/selectize-plugin-a11y.js

@@ -42,7 +42,7 @@ Selectize.define("selectize-plugin-a11y", function (options) {
               // random IDs are assigned when .selectize() is called, but we're
               // doing it here to limit the scope of changes.
               var kids = self.$dropdown_content[0].children;
-              for (i = 0; i < kids.length; i++) {
+              for (var i = 0; i < kids.length; i++) {
                 var attrs = kids[i].attributes;
                 if (!attrs.role) {
                   kids[i].setAttribute("role", "option");

srcts/build/external_libs.ts

@@ -10,6 +10,12 @@ import globalsPlugin from "esbuild-plugin-globals";
 const opts = {
   bundle: false,
   sourcemap: false,
+  // Oddly, esbuild seems to use the top-level tsconfig.json file even when just
+  // minifying JS to JS. Because that tsconfig file has "strict":true, esbuild
+  // ends up adding "use strict" to the top of each minified JS file, which can
+  // alter behavior. To avoid this, we have a separate tsconfig file with
+  // "alwaysStrict":false.
+  tsconfig: "srcts/build/external_libs_tsconfig.json",
 };
 
 readdir(outDir + "datepicker/js/locales/").then(async (localeFiles) => {

srcts/build/external_libs_tsconfig.json

@@ -0,0 +1,6 @@
+{
+    "compilerOptions": {
+      "target": "ES5",
+      "alwaysStrict": false
+    }
+}

tools/selectize-patches/000-selectize-a11y-assign-id.patch

@@ -11,7 +11,7 @@ index e3cd799e..1d494f88 100644
 +              // random IDs are assigned when .selectize() is called, but we're
 +              // doing it here to limit the scope of changes.
 +              var kids = self.$dropdown_content[0].children;
-+              for (i = 0; i < kids.length; i++) {
++              for (var i = 0; i < kids.length; i++) {
 +                var attrs = kids[i].attributes;
 +                if (!attrs.role) {
 +                  kids[i].setAttribute("role", "option");