Fix missing dialog icons in GTK 3.24.48

Upstream caused a patch conflict:
https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/7587

The changes in #114 (9129a63) to fix the patch were not 100%
complete. The icon variable was set outside [update_accessible_name] of
the function [setup_type] that actually sets this icon. Even though
repeating the case select is a bit like code duplication, it works and
fixes the regression.

PKGBUILD: Update checksums

- appearance__message-dialogs.patch
- gtk-3.24.48.tar.gz

Release 3.24.43-2

Add patch: a42ef19

Upstream 3.24.43

Upstream 3.24.42

Upstream 3.24.41

Upstream 3.24.40

Upstream 3.24.39

PKGBUILD: Bump version to 3.24.38-3

Add patch: 4b9c95e

PKGBUILD: Exclude demos

The README states that demos, examples and tests are excluded, yet
they're being built and included. Whoops.

Addresses AUR comment:
https://aur.archlinux.org/packages/gtk3-classic#comment-926806