Convert to old JS to fix build

Author: GarboMuffin

lib/zipEntries.js

@@ -257,19 +257,19 @@ ZipEntries.prototype = {
         this.zipCommentLength = 0;
         this.zipComment = [];
 
-        let possibleHeaders = 0;
+        var possibleHeaders = 0;
 
         // Without central directory, have to just search for file entry magic bytes
-        const length = this.reader.length;
-        for (let i = 0; i < length - 4; i++) {
+        var length = this.reader.length;
+        for (var i = 0; i < length - 4; i++) {
             if (
                 this.reader.byteAt(i) === 0x50 &&
                 this.reader.byteAt(i + 1) === 0x4B &&
                 this.reader.byteAt(i + 2) === 0x03 &&
                 this.reader.byteAt(i + 3) === 0x04
             ) {
                 possibleHeaders++;
-                const zipEntry = this.tryRecoverFileEntry(i);
+                var zipEntry = this.tryRecoverFileEntry(i);
                 if (zipEntry) {
                     this.files.push(zipEntry);
                 }
@@ -280,7 +280,7 @@ ZipEntries.prototype = {
             if (possibleHeaders === 0) {
                 throw new Error("Corrupted zip: no central directory or any file headers");
             }
-            throw new Error(`Corrupted zip: no central directory, and ${possibleHeaders} possible local headers could not be recovered`);
+            throw new Error("Corrupted zip: no central directory, and " + possibleHeaders + " possible local headers could not be recovered");
         }
     },
     /**
@@ -291,7 +291,7 @@ ZipEntries.prototype = {
     tryRecoverFileEntry: function(index) {
         this.reader.setIndex(index);
 
-        const zipEntry = new ZipEntry({
+        var zipEntry = new ZipEntry({
             zip64: this.zip64
         }, this.loadOptions);