[libgsystem] README: Update for deprecation

[Colin Walters <walters src gnome org>]

commit 6f5b70922ee1f329c24b8a74f61be4f4c0c946ef
Author: Colin Walters <walters verbum org>
Date:   Fri Feb 13 05:10:08 2015 -0500

    README: Update for deprecation

 README |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)
---
diff --git a/README b/README
index 13fa05f..b6b6579 100644
--- a/README
+++ b/README
@@ -1,4 +1,15 @@
-libgsystem is intended to be used as a git external for components
+Pending deprecation
+-------------------
+
+This library is pending deprecation and no new APIs will be
+added.  For more information, see:
+
+https://mail.gnome.org/archives/desktop-devel-list/2015-February/msg00120.html
+
+Old README
+----------
+
+libgsystem was intended to be used as a git external for components
 that depend on GLib, but accept a hard dependency on things which are
 difficult to do in GLib itself.  For example, the local-alloc API
 depends on GCC/clang.