Ticket #28966: 28966.patch

Gruntfile.js

@@ -161 +161 @@
                 cssjanus: {
                         core: {
                                 options: {
-                                        swapLtrRtlInUrl: false
+                                        swapLtrRtlInUrl: false,
+                                        processContent: function( src ) {
+                                                return src.replace( /url\((.+?)\.css\)/g, 'url($1-rtl.css)' );
+                                        }
                                 },
                                 expand: true,
                                 cwd: SOURCE_DIR,