Remove dead code guarded with "#if 0 … #endif" (#2338)

This code has been neutralized for many years now and served no purpose
other than cluttering up the code. We obviously don't need it and it's
out of date anyway.

If there's ever any reason to restore (parts of) it, we have git for
that. But we don't need to keep commented out code around.

include/floating.h

@@ -76,25 +76,6 @@ void floating_center(Con *con, Rect rect);
  */
 void floating_move_to_pointer(Con *con);
 
-#if 0
-/**
- * Removes the floating client from its workspace and attaches it to the new
- * workspace. This is centralized here because it may happen if you move it
- * via keyboard and if you move it using your mouse.
- *
- */
-void floating_assign_to_workspace(Client *client, Workspace *new_workspace);
-
-/**
- * Called whenever the user clicks on a border (not the titlebar!) of a
- * floating window. Determines on which border the user clicked and launches
- * the drag_pointer function with the resize_callback.
- *
- */
-int floating_border_click(xcb_connection_t *conn, Client *client,
-                          xcb_button_press_event_t *event);
-
-#endif
 /**
  * Called when the user clicked on the titlebar of a floating window.
  * Calls the drag_pointer function with the drag_window callback
@@ -118,32 +99,6 @@ void floating_resize_window(Con *con, const bool proportional, const xcb_button_
  */
 void floating_check_size(Con *floating_con);
 
-#if 0
-/**
- * Changes focus in the given direction for floating clients.
- *
- * Changing to the left/right means going to the previous/next floating client,
- * changing to top/bottom means cycling through the Z-index.
- *
- */
-void floating_focus_direction(xcb_connection_t *conn, Client *currently_focused,
-                              direction_t direction);
-
-/**
- * Moves the client 10px to the specified direction.
- *
- */
-void floating_move(xcb_connection_t *conn, Client *currently_focused,
-                   direction_t direction);
-
-/**
- * Hides all floating clients (or show them if they are currently hidden) on
- * the specified workspace.
- *
- */
-void floating_toggle_hide(xcb_connection_t *conn, Workspace *workspace);
-
-#endif
 /**
  * This is the return value of a drag operation like drag_pointer.
  *

include/manage.h

@@ -35,19 +35,3 @@ void restore_geometry(void);
 void manage_window(xcb_window_t window,
                    xcb_get_window_attributes_cookie_t cookie,
                    bool needs_to_be_mapped);
-
-#if 0
-/**
- * reparent_window() gets called when a new window was opened and becomes a
- * child of the root window, or it gets called by us when we manage the
- * already existing windows at startup.
- *
- * Essentially, this is the point where we take over control.
- *
- */
-void reparent_window(xcb_connection_t *conn, xcb_window_t child,
-                     xcb_visualid_t visual, xcb_window_t root, uint8_t depth,
-                     int16_t x, int16_t y, uint16_t width, uint16_t height,
-                     uint32_t border_width);
-
-#endif

include/workspace.h

@@ -50,17 +50,6 @@ void extract_workspace_names_from_bindings(void);
  */
 Con *create_workspace_on_output(Output *output, Con *content);
 
-#if 0
-/**
- * Sets the name (or just its number) for the given workspace. This has to
- * be called for every workspace as the rendering function
- * (render_internal_bar) relies on workspace->name and workspace->name_len
- * being ready-to-use.
- *
- */
-void workspace_set_name(Workspace *ws, const char *name);
-#endif
-
 /**
  * Returns true if the workspace is currently visible. Especially important for
  * multi-monitor environments, as they can have multiple currenlty active