Bug 1687116 - Enabling Help and Feedback links in Windows and Linux in the About Dialog. r=Gijs

Enabling help and feedback links in Windows and Linux by making sure the functions for these are available in the About dialog in Windows and Linux builds.

Differential Revision: https://phabricator.services.mozilla.com/D102512

browser/base/content/aboutDialog.xhtml

@@ -32,6 +32,8 @@
         >
 #ifdef XP_MACOSX
 #include macWindow.inc.xhtml
+#else
+  <script src="chrome://browser/content/utilityOverlay.js"/>
 #endif
 
   <linkset>