Update glib to 2.76.3 and Flatpak platform to 7.2

[ryonakano]

• elementary Flatpak runtime
  • Update to 7.2
• glib
  • Remove internal_pcre config opt because it was removed since glib 2.69.0: GNOME/glib@9fbd7f3
  • Update to 7.26.3

The reason to update glib to 7.26.3

When we apply the other changes in this commit and #122, building succeeds but linking being failed with these warnings:

/usr/lib/gcc/x86_64-unknown-linux-gnu/12.2.0/../../../../x86_64-unknown-linux-gnu/bin/ld: /usr/lib/x86_64-linux-gnu/libgtk-3.so: undefined reference to `g_task_set_static_name'
/usr/lib/gcc/x86_64-unknown-linux-gnu/12.2.0/../../../../x86_64-unknown-linux-gnu/bin/ld: /usr/lib/x86_64-linux-gnu/libpango-1.0.so: undefined reference to `g_string_free_and_steal'

This is because both functions listed here are only available from glib 2.76.x:

• https://docs.gtk.org/gio/method.Task.set_static_name.html
• https://docs.gtk.org/glib/method.String.free_and_steal.html

So, I got the tarball from https://download.gnome.org/sources/glib/2.76. Also, I re-created the appinfo patch from the git source of 2.76.3.

[donadigo]

Thanks so much!