Finish announcement for 2.1 release.

Author: davidchisnall

ANNOUNCE

@@ -1,11 +1,18 @@
 GNUstep Objective-C Runtime 2.1
 =================================
 
-This is first update to the second major release of the GNUstep Objective-C
+This is the first update to the second major release of the GNUstep Objective-C
 runtime (a.k.a.  libobjc2).  This runtime was designed to support the features
 of modern dialects of Objective-C for use with GNUstep and other Objective-C
 programs.
 
+*NOTE:* This is the first release to use submodules.  If you are downloading
+the sources from git, please make sure that you do a recursive clone.  If you
+forget, the build system will give you instructions to correct this.
+Tarballs from GitHub do not include submodules, so if you are downloading the
+tarball then you will need to download the submodule separately.
+
+
 Highlights of this release include:
 
 - Numerous improvements to the Objective-C++ exception interoperation code.
@@ -53,6 +60,16 @@ Alternatively, a tarball is available from:
 https://github.com/gnustep/libobjc2/archive/v2.1.zip
 https://github.com/gnustep/libobjc2/archive/v2.1.tar.gz
 
+The submodule is available from:
+
+https://github.com/Tessil/robin-map/archive/757de82.zip
+https://github.com/Tessil/robin-map/archive/757de82.tar.gz
+
+This will extract as robin-map-757de829927489bee55ab02147484850c687b620.
+You must move the contents of that directory into third_party/robin_map in the
+libobjc2 tree.
+
+
 The runtime library is responsible for implementing the core features of the
 object model, as well as exposing introspection features to the user.  The
 GNUstep runtime implements a superset of Apple's Objective-C Runtime APIs.