fix for less.js issue 132

issue132.diff

diff --git a/lib/less/tree/url.js b/lib/less/tree/url.js
index 33b05b9..f53f1ea 100644
--- a/lib/less/tree/url.js
+++ b/lib/less/tree/url.js
@@ -14,8 +14,15 @@ tree.URL = function (val, paths) {
 };
 tree.URL.prototype = {
     toCSS: function () {
-        return "url(" + (this.attrs ? 'data:' + this.attrs.mime + this.attrs.charset + this.attrs.base64 + this.attrs.data
-                                    : this.value.toCSS()) + ")";
+        var attrs = this.attrs,
+            val = this.value,
+            paths = this.paths;
+        // adjust the paths for lessc
+        if (val && !/^(?:https?:\/|file:\/)?\//.test(val.value) && paths.length > 0 && typeof(window) === 'undefined') {
+            val.value = paths[0].replace(/\/?$/, '/') + val.value;
+        }
+        return "url(" + (attrs ? 'data:' + attrs.mime + attrs.charset + attrs.base64 + attrs.data
+                                    : val.toCSS()) + ")";
     },
     eval: function (ctx) {
         return this.attrs ? this : new(tree.URL)(this.value.eval(ctx), this.paths);