Circumnavigate compiler warning message.
warning: copying delegates is not supported

The use of show_uri is deprecated since GTK 4.10. The suggested alternative
is to use UriLauncher, however for help UriLauncher has a bug that results
in a "Document Not Found" message when used in flatpack.
There is no intention to fix this bug so we will continue to use show_uri.
This stops the deprecate warning and hopefully stops anyone mistakenly
coding a switch to UriLauncher.

(cherry picked from commit 80b2aa4c)

(cherry picked from commit cb5ba065)

Local function support was introduced by this commit:
https://gitlab.gnome.org/GNOME/vala/-/commit/048aaba0cd88b784fe9fa421dbad494019abd42e

(cherry picked from commit fd88ee6a)

A fix for this is in vala release 0.56.15
https://gitlab.gnome.org/GNOME/vala/-/issues/1408

Correct the previous commit.

Compile against vala fixes for this bug:
https://gitlab.gnome.org/GNOME/vala/-/commit/ae2cbcd0011081581bef406fcbfcd1e86b7dacd3

src/gnome-nibbles.vala:146:13-146:18: error: `inline' modifier not applicable on creation methods
  146 |     private inline Nibbles ()
      |             ^~~~~~

We use features from vala 0.58 but maintain support for vala version
0.56 as this is a Stable Long-term Support release.

Make it easier to test nibbles on older O/S.

This reverts commit 9eb28e81.

This reverts commit a65af690.

This reverts commit f2da0111.

Make it easier to test nibbles on older O/S.

We use features from vala 0.58 but maintain support for vala version
0.56 as this is a Stable Long-term Support release.

Conform more with Gnome's style.

(cherry picked from commit 91441d53)

Fix up link tests.

The symbol of an extra life on the board matches the symbol for the life of a worm.

Fixes #32

I'm not maintaining this anymore.