buflist: add variable ${current_buffer} in bar item evaluation

src/plugins/buflist/buflist-bar-item.c

@@ -168,6 +168,11 @@ buflist_bar_item_buflist_cb (const void *pointer, void *data,
                 goto error;
         }
 
+        /* current buffer */
+        weechat_hashtable_set (buflist_hashtable_extra_vars,
+                               "current_buffer",
+                               (current_buffer) ? "1" : "0");
+
         /* buffer number */
         number = weechat_hdata_integer (buflist_hdata_buffer,
                                         ptr_buffer, "number");

src/plugins/buflist/buflist-command.c

@@ -99,6 +99,9 @@ buflist_command_init ()
            "buflist.format.buffer; this can be used in option "
            "buflist.format.buffer_current to just change the background color "
            "for example\n"
+           "    - ${current_buffer}: a boolean (\"0\" or \"1\"), \"1\" if "
+           "this is the current buffer; it can be used in a condition: "
+           "${if:${current_buffer}?...:...}\n"
            "    - ${format_number}: indented number with separator "
            "(evaluation of option buflist.format.number)\n"
            "    - ${number}: indented number, for example \" 1\" if there "