Remove trailing whitespace.

Also, the script is a one-liner, stolen from [1]:

ack --print0 -l '[ \t]+$' | xargs -0 -n1 perl -pi -e 's/[ \t]+$//'

[1]
https://stackoverflow.com/questions/149057/how-to-remove-trailing-whitespace-of-all-files-recursively

src/icon.c

@@ -669,7 +669,7 @@ void update_icon_pixmap(WIcon *icon)
 		XFreePixmap(dpy, icon->pixmap);
 
 	icon->pixmap = None;
- 
+
 	/* Create the pixmap */
 	if (icon->file_image)
 		icon_update_pixmap(icon, icon->file_image);