Add wx/gtk/private/wrapgtk.h wrapping gtk/gtk.h in pragmas disabling
these warnings and include it everywhere instead of directly including
gtk/gtk.h.
Also include wx/gtk/private/gtk2-compat.h from this wrapper header as it
was included by 90% of the files including gtk/gtk.h itself and it seems
to be better and simpler to just always include it.
Use wx_is_at_least_gtk2(minor) instead of gtk_check_version(2, minor)
because it is more clear and also works as expected (i.e. returns true)
when using GTK+ 3 instead of creating difficult to notice bugs in the
code by failing the version check in this case.
See #18004.
This is a simple animated control indicating some program activity.
Provide native GTK+ (for > 2.20) and OS X implementations as well as a generic
one used under MSW.
Update the sample and the documentation.
