{
    let util = {};
    Components.utils.import("resource://gipsy/util.jsm", util);

    let myId    = "gipsy-button"; // ID of button to add
    let afterId = "search-container";    // ID of element to insert after
    let navBar  = document.getElementById("nav-bar");

    if (navBar && !util.get_bool_pref('btn_toolbar_added')) {
        let curSet  = navBar.currentSet.split(",");
        if (curSet.indexOf(myId) == -1) {
            let pos = curSet.indexOf(afterId) + 1 || curSet.length;
            let set = curSet.slice(0, pos).concat(myId).concat(curSet.slice(pos));

            navBar.setAttribute("currentset", set.join(","));
            navBar.currentSet = set.join(",");
            document.persist(navBar.id, "currentset");
            try {
                BrowserToolboxCustomizeDone(true);
            } catch (e) {}
            util.set_bool_pref('btn_toolbar_added', true);
        }
    }
}

@@ -4,17 +4,22 @@
     let 
-u
+GipsyU
 til = %7B%7D
@@ -78,17 +78,22 @@
 l.jsm%22, 
-u
+GipsyU
 til);%0D%0A%0D
@@ -302,17 +302,22 @@
 Bar && !
-u
+GipsyU
 til.get_
@@ -880,17 +880,22 @@
         
-u
+GipsyU
 til.set_

Rename 'util' to 'GipsyUtil' in overlay.