Correct formatting of locale to make it compatible with l10n (safari issue)

web/compatibility.js

@@ -452,16 +452,20 @@ if (typeof PDFJS === 'undefined') {
 
 // Checks if navigator.language is supported
 (function checkNavigatorLanguage() {
-  if ('language' in navigator)
+  if ('language' in navigator &&
+      /^[a-z]+(-[A-Z]+)?$/.test(navigator.language)) {
     return;
-  Object.defineProperty(navigator, 'language', {
-    get: function navigatorLanguage() {
-      var language = navigator.userLanguage || 'en-US';
-      return language.substring(0, 2).toLowerCase() +
-        language.substring(2).toUpperCase();
-    },
-    enumerable: true
-  });
+  }
+  function formatLocale(locale) {
+    var split = locale.split(/[-_]/);
+    split[0] = split[0].toLowerCase();
+    if (split.length > 1) {
+      split[1] = split[1].toUpperCase();
+    }
+    return split.join('-');
+  }
+  var language = navigator.language || navigator.userLanguage || 'en-US';
+  PDFJS.locale = formatLocale(language);
 })();
 
 (function checkRangeRequests() {

web/viewer.js

@@ -1666,7 +1666,7 @@ document.addEventListener('DOMContentLoaded', function webViewerLoad(evt) {
   }
 
 //#if !(FIREFOX || MOZCENTRAL)
-  var locale = navigator.language;
+  var locale = PDFJS.locale || navigator.language;
   if ('locale' in hashParams)
     locale = hashParams['locale'];
   mozL10n.setLanguage(locale);