add fixedWidthGutter option

lib/ace/editor.js

@@ -2385,6 +2385,7 @@ config.defineOptions(Editor.prototype, "editor", {
     maxLines: "renderer",
     minLines: "renderer",
     scrollPastEnd: "renderer",
+    fixedWidthGutter: "renderer",
 
     scrollSpeed: "$mouseHandler",
     dragDelay: "$mouseHandler",

lib/ace/layer/gutter.js

@@ -168,7 +168,7 @@ var Gutter = function(parentEl) {
         this.element = dom.setInnerHtml(this.element, html.join(""));
         this.element.style.height = config.minHeight + "px";
         
-        if (this.session.$useWrapMode)
+        if (this.$fixedWidth || this.session.$useWrapMode)
             lastLineNumber = this.session.getLength();
         
         var gutterWidth = ("" + lastLineNumber).length * config.characterWidth;
@@ -181,6 +181,8 @@ var Gutter = function(parentEl) {
         }
     };
 
+    this.$fixedWidth = false;
+    
     this.$showFoldWidgets = true;
     this.setShowFoldWidgets = function(show) {
         if (show)

lib/ace/virtual_renderer.js

@@ -1655,6 +1655,12 @@ config.defineOptions(VirtualRenderer.prototype, "renderer", {
         },
         initialValue: 0,
         handlesSet: true
+    },
+    fixedWidthGutter: {
+        set: function(val) {
+            this.gutterLayer.fixedWidth = !!val;
+            this.$loop.schedule(this.CHANGE_GUTTER);
+        }
     }
 });