Build failure LMDE6 Debian 12

A lot of warnings
Where could the problem be?
maybe this?
_Shard "harfbuzz" may be incompatible with Crystal 1.6.0_

```
axel@chieftech:/tmp/rtfm-0.6.0$ make
shards install
Resolving dependencies
Fetching https://github.com/hugopl/fzy.git
Fetching https://github.com/hugopl/libadwaita.cr.git
Fetching https://github.com/crystal-lang/crystal-sqlite3.git
Fetching https://github.com/hugopl/gtk4.cr.git
Fetching https://github.com/hugopl/gi-crystal.git
Fetching https://github.com/hugopl/pango.cr.git
Fetching https://github.com/hugopl/harfbuzz.cr.git
Fetching https://github.com/crystal-lang/crystal-db.git
Installing fzy (0.6.0)
Installing gi-crystal (0.24.0)
Postinstall of gi-crystal: shards build
Installing harfbuzz (0.2.0)
Installing pango (0.3.1)
Installing gtk4 (0.17.0)
Installing libadwaita (1.0.0 at cffabb5)
Installing db (0.12.0)
Installing sqlite3 (0.20.0)
Shard "harfbuzz" may be incompatible with Crystal 1.6.0
./bin/gi-crystal
info - Starting at 2025-02-23 17:02:46 +01:00, project dir: /tmp/rtfm-0.6.0
info - Gi-Crystal version 0.24.0, built with Crystal 1.6.0.
info - Generating bindings at /tmp/rtfm-0.6.0/lib/gi-crystal/src/auto
info - Using binding config at /tmp/rtfm-0.6.0/src/bindings/webkit2/binding.yml
info - Using binding config at /tmp/rtfm-0.6.0/lib/gi-crystal/src/bindings/g_lib/binding.yml
info - Using binding config at /tmp/rtfm-0.6.0/lib/gi-crystal/src/bindings/g_object/binding.yml
info - Using binding config at /tmp/rtfm-0.6.0/lib/gi-crystal/src/bindings/gio/binding.yml
info - Using binding config at /tmp/rtfm-0.6.0/lib/harfbuzz/src/bindings/harfbuzz/binding.yml
info - Using binding config at /tmp/rtfm-0.6.0/lib/pango/src/bindings/pango/binding.yml
info - Using binding config at /tmp/rtfm-0.6.0/lib/gtk4/src/bindings/gdk/binding.yml
info - Using binding config at /tmp/rtfm-0.6.0/lib/gtk4/src/bindings/gsk/binding.yml
info - Using binding config at /tmp/rtfm-0.6.0/lib/gtk4/src/bindings/gtk/binding.yml
info - Using binding config at /tmp/rtfm-0.6.0/lib/libadwaita/src/bindings/binding.yml
info - WebKit - No binding config found for Soup-3.0.
info - WebKit - No binding config found for JavaScriptCore-6.0.
warn - WebKit - Boxed not working for enums
warn - soup_form_decode - Unknown conversion to crystal for GHash
warn - soup_form_decode_multipart - Unknown conversion to crystal for GHash
warn - soup_header_parse_param_list - Unknown conversion to crystal for GHash
warn - soup_header_parse_param_list_strict - Unknown conversion to crystal for GHash
warn - soup_header_parse_semi_param_list - Unknown conversion to crystal for GHash
warn - soup_header_parse_semi_param_list_strict - Unknown conversion to crystal for GHash
warn - soup_server_add_early_handler - Unknown conversion to crystal for GHash
warn - soup_server_add_handler - Unknown conversion to crystal for GHash
warn - Generator::VFuncGen - Unknown conversion to crystal for GHash
warn - g_cancellable_connect - Callback without user_data!
warn - Gio::ActionEntry padding field - Unknown conversion to crystal for fixed size array.
warn - Gio::DBusInterfaceVTable padding field - Unknown conversion to crystal for fixed size array.
warn - Gio::DBusSubtreeVTable padding field - Unknown conversion to crystal for fixed size array.
warn - jsc_class_add_property - Callback without user_data!
warn - jsc_value_object_define_property_accessor - Callback without user_data!
info - gtk_render_activity - No binding config found for cairo-1.0.
info - gtk_image_new_from_pixbuf - No binding config found for GdkPixbuf-2.0.
info - gtk_snapshot_append_cairo - No binding config found for Graphene-1.0.
warn - Gtk::BuildableParser padding field - Unknown conversion to crystal for fixed size array.
warn - gsk_border_node_get_widths - Unknown conversion to crystal for fixed size array.
info - Gdk - No binding config found for PangoCairo-1.0.
warn - Gdk - SeatCapabilities::All (0xf) doesn't have all possible bits set (0x1f).
warn - Gdk::TimeCoord axes field - Unknown conversion to crystal for fixed size array.
info - HarfBuzz - No binding config found for freetype2-2.0.
warn - HarfBuzz - Interface constant not supported.
info - GdkPixbuf - No binding config found for GModule-2.0.
warn - gdk_pixbuf_get_options - Unknown conversion to crystal for GHash
make: *** Keine Regel vorhanden, um das Ziel „.WAIT“,
benötigt von „all“, zu erstellen. Schluss.

```