Meson: some more improvements

commit 327e4c0b

Meson: Pass all dependencies to gnome.generate_gir()

This is needed when for example gtk4 is built as subproject so it needs
to find gtk-4.git from build directory.

commit 6c61f7c9

Meson: There is no reason for gtksource_dep to be different with MSVC

commit 18744fa7

meson: Use summary() instead of custom formatted string

commit 9a73a44b

Bump glib dependency to 2.66

This is the version required by gtk4. This fix meson error on distro
like Ubuntu 20.04 LTS that has glib 2.64 but not gtk4, so the
configuration of gtk4 subproject fails because of too old glib version
found and it cannot fallback to glib subproject any more because
gtksourceview is using the system dependency already.