[pango/macos-introspection] Use gobject-introspection subproject on MacOS

[Matthias Clasen <matthiasc src gnome org>]

commit 658cf7e5eeb103d73238aec5ce31459ca8e24346
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Jan 5 23:41:37 2021 -0500

    Use gobject-introspection subproject on MacOS

 meson.build | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/meson.build b/meson.build
index 5bd193c8..4c016f7d 100644
--- a/meson.build
+++ b/meson.build
@@ -211,6 +211,10 @@ gio_dep = dependency('gio-2.0', version: glib_req_version,
                          fallback: ['glib', 'libgio_dep'])
 pango_deps += [glib_dep, gobject_dep, gio_dep]
 
+if host_system == 'darwin'
+  subproject('gobject-introspection')
+endif
+
 fribidi_dep = dependency('fribidi', version: fribidi_req_version,
                          fallback: ['fribidi', 'libfribidi_dep'],
                          default_options: ['docs=false'])