We're a normal application, so we can use the normal way to hook up code
into builder files, which is using dlsym() for the function pointers.
There's no need to to extra work exporting static symbols.
gtk_builder_connect_signals() is no longer necessary, because all the
setup that made it necessary to have this extra step is now done
automatically via the closure functions.
This is pretty unused and gets in the way of the next steps.
A potential side effect is that for templates the widget was passed as
the user data argument. If that turns out to be important, we have to
special case that situation.
The "iconified" state is mostly an X11-ism; every other platform calls
this state "minimized" because it may not involve turning a window into
an icon at all.
The GtkTextHistory helper provides the fundamental undo/redo stack that
can be integrated with other text widgets. It allows coalescing related
actions to reduce both the number of undo actions to the user as well as
the memory overhead.
A new istring helper is used by GtkTextHistory to allow for "inline
strings" that gracefully grow to using allocations with g_realloc(). This
ensure that most undo operations require no additional allocations other
than the struct for the action itself.
A queue of undoable and redoable actions are maintained and the link for
the queue is embedded in the undo action union. This allows again, for
reducing the number of allocations involved for undo operations.
This creates a new GtkTextViewChild that can manage overlay children at
given x,y offsets in buffer coordinates. This simplifies GtkTextView by
extracting this from GtkTextWindow as well as providing a real widget for
the borders.
With this change, we also rename gtk_text_view_add_child_in_window() to
gtk_text_view_add_overlay(). For those that were using
GTK_TEXT_WINDOW_WIDGET, they can use a GtkOverlay. It does not appear
that anyone was using GTK_TEXT_WINDOW_(LEFT|RIGHT|TOP|BOTTOM) for widgets
in this fashion, but that can be done by setting a gutter widget with
gtk_text_view_set_gutter(). We can make GtkTextViewChild public if
necessary to simplify this should it become necessary.
GtkTextViewChild will setup a CSS node of either "text" or "border"
depending on the GtkTextWindowType.
The old GtkTextViewChild has been renamed to AnchoredChild as it is only
used for widgets with anchors in the GtkTextBuffer. This also removes the
use of allocated GSList and instead embeds a GQueue and GList to save a
few extraneous allocations.
