split x_setup() into two. dpy_init() for setting up the display and

checking the X config, and x_setup to set up the screens.

There's an ordering problem that means that some of this init needs to
come after the config is parsed, the rest should ideally happen before
though. This is a rough split, it will be refined later. Again, needed
for an upcoming change.

ok okan.

calmwm.h

@@ -309,7 +309,7 @@ int			 input_keycodetrans(KeyCode, u_int, enum ctltype *,
 			     char *);
 
 int			 x_errorhandler(Display *, XErrorEvent *);
-void			 x_setup(char *display_name);
+void			 x_setup(void);
 char			*x_screenname(int);
 void			 x_setupscreen(struct screen_ctx *, u_int);
 __dead void		 usage(void);