Customize xscreensaver's unlock dialog image.

patch-mylogo

--- driver/lock.c~	2011-09-24 19:13:50.000000000 -0500
+++ driver/lock.c	2012-09-26 05:03:57.116385782 -0500
@@ -686,7 +686,7 @@ make_passwd_window (saver_info *si,
 					   si->passwd_dialog, cmap,
 					   pw->background, 
 					   &pw->logo_pixels, &pw->logo_npixels,
-					   &pw->logo_clipmask, True);
+					   &pw->logo_clipmask, -1);
     }
   else /* On successive prompts, just resize the window */
     {
--- utils/logo.c~	2006-02-10 21:12:53.000000000 -0600
+++ utils/logo.c	2012-09-26 05:02:12.134183020 -0500
@@ -28,6 +28,7 @@
 
 #include "images/logo-50.xpm"
 #include "images/logo-180.xpm"
+#include "images/logo.xpm"
 
 /* Returns a pixmap of the xscreensaver logo.
  */
@@ -47,7 +48,8 @@ xscreensaver_logo (Screen *screen, Visua
   unsigned char *mask = 0;
 
   image = minixpm_to_ximage (dpy, visual, cmap, depth, background_color,
-                             (big_p ? logo_180_xpm : logo_50_xpm),
+                             (big_p ? (big_p > 0 ? logo_180_xpm : logo_xpm)
+                                    : logo_50_xpm),
                              &iw, &ih, pixels_ret, npixels_ret,
                              (mask_ret ? &mask : 0));
 

Could you explain how you implemented this patch?