gobject-introspection: update to 1.70.0.

Add upstream patch to fix build with latest meson.

1.70.0 - 2021-09-17
-------------------

* Update the GIR data for GLib, GObject, and GIO

1.69.0 - 2021-08-24
-------------------

* Fix build when gobject-introspection is a subproject :mr:`266`
* Add more float types :issue:`384`, :mr:`269`
* Make test suite work with cross-related options :issue:`227`
* Fix several leaks found by Coverity :mr:`272`
* Fix enum member c:identifier :mr:`264`
* Add g-ir-doc-tool man page :mr:`284`
* Export warnlib sources as variables :mr:`287`
* Update the GLib annotations :mr:`288`
* Add "final" class attribute :mr:`257`, :mr:`291`
* Add option to make .gir files installation paths configurable :mr:`63`
* Handle constructors with mismatched GTypes :issue:`399`, :mr:`292`
* Add property accessors annotations :issue:`13`, :mr:`279`

(wiz)