Log Message:
Update glib2 to 2.60.2

GLib's move to meson from autotools means we are effectively starting
from scratch with non-linux build fixes. Support for python 2 has
also been dropped (given that meson requires python 3). I replaced
sysutils/gio-fam with a build option.

The full lengthy list of changes is available from:

  https://gitlab.gnome.org/GNOME/glib/tags/2.60.2

Some highlights:
* Improve network status detection with NetworkManager (!781)
* Add async GIO API: g_file_query_default_handler_async(), \ 
g_app_info_launch_uris_async() (#1249, #1347)
* Add overlay support to g_resources_get_info(). (#1445)
* Add writev() and writev_all() APIs to GOutputStream and GPollableOutputStream,
  and provide implementations of them for many subclasses. (#1431)
* Hide bind mounts from GIO mount listings. (#1271)
* Automatically realign data passed to `g_variant_new_from_bytes()` or
  `g_variant_new_from_data()` if it is not correctly aligned. This prevents
  misaligned accesses on architectures which don’t support them. Callers should
  still aim to correctly align data to get higher performance. (#1342)
* Support `ld -b binary` (on platforms which support it; i.e. Linux) to provide
  large pre-compiled `GResource` resources with a fast compilation time. \ 
(#1489+* Drop Python 2 support and require Python 3.4+. See discussion on
  https://mail.gnome.org/archives/desktop-devel-list/2018-July/msg00004.html.
  (!196)
* Various fixes to eliminate thread races, found by thread sanitizer (tsan).