--- a/src/configure.c	
+++ a/src/configure.c	
@@ -44,6 +44,8 @@ gint cfg_action = DEFAULT;
 gchar **cfg_lines = NULL;
 FILE *cfg_file = NULL;
 
+prefs_t *options;
+
 void
 print_help (const gchar *myname)
 {
--- a/src/configure.h	
+++ a/src/configure.h	
@@ -52,7 +52,7 @@ typedef struct
     GList *mountpoint_force;
 } prefs_t;
 
-prefs_t *options;
+extern prefs_t *options;
 
 
 prefs_t *cfg_new (void);
--- a/src/interface.c	
+++ a/src/interface.c	
@@ -31,6 +31,8 @@ 
 gint block_size_status;
 gint timeout_status;
 
+GtkWidget *mwindow;
+
 GtkWidget *list_box, *list_scroll;
 
 GtkWidget *status_hbox;
@@ -39,6 +41,14 @@ GtkWidget *status_bar_timeout;
 
 gint capacity_resize_timeout = 0;
 
+GtkTreeModel *list_treemodel;
+GtkWidget *list_treeview;
+
+GtkWidget *menu_frame;
+GtkWidget *tool_frame;
+
+gboolean gui_color_update;
+
 void gui_capacity_column_resize_end (gpointer data)
 {
     capacity_resize_timeout = 0;
--- a/src/interface.h	
+++ a/src/interface.h	
@@ -22,15 +22,15 @@ 
 #define GTKDISKFREE_INTERFACE_H
 #include <gtk/gtk.h>
 #include "main.h"
-GtkWidget *mwindow;
+extern GtkWidget *mwindow;
 
-GtkTreeModel *list_treemodel;
-GtkWidget *list_treeview;
+extern GtkTreeModel *list_treemodel;
+extern GtkWidget *list_treeview;
 
-GtkWidget *menu_frame;
-GtkWidget *tool_frame;
+extern GtkWidget *menu_frame;
+extern GtkWidget *tool_frame;
 
-gint gui_color_update;
+extern gboolean gui_color_update;
 
 void gui_list_columns_disp_update (void);
 void gui_statusbar_timeout_update (GtkWidget *widget, order_t action);