/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/ is in libclanlib-dev 1.0~svn3827-4.1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/button_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/checkbox_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/frame_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/image_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/inputbox_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/label_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/listbox_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/menu_item_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/menu_node_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/menu_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/progressbar_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/radiobutton_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/richedit_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/scrollbar_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/stylemanager_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/treeitem_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/treeview_silver.h
/usr/include/ClanLib-1.0/ClanLib/GUIStyleSilver/window_silver.h