Fix build with -fno-common

Index: xutils.c
--- xutils.c.orig
+++ xutils.c
@@ -37,6 +37,11 @@
 #include "xutils.h"
 
 /*
+ * global variable
+ */
+Display *display;
+
+/*
  * global variables for this file
  */
 int		x_fd;
@@ -47,6 +52,10 @@ char		*Geometry = "";
 GC		NormalGC;
 XpmIcon		wmgen;
 Pixmap		pixmask;
+Window		Root;
+Window		win, iconwin;
+int		screen;
+int		DisplayDepth;
 
 extern char	TimeColor[30];
 extern char	BackgroundColor[30];