Merge branch 'gtkdoc-dep' into 'master'

gtk-doc: Ensure we have recent enough version

See merge request GNOME/glib!1261

docs/reference/meson.build

@@ -29,6 +29,12 @@ gtkdoc_common_scan_args = [
   '--ignore-decorators=' + '|'.join(ignore_decorators),
 ]
 
+if get_option('gtk_doc')
+  # Check we have the minimum gtk-doc version required. Older versions won't
+  # generate correct documentation.
+  dependency('gtk-doc', version : '>=1.32')
+endif
+
 subdir('gio')
 subdir('glib')
 subdir('gobject')