Down-integrate some code from an internal branch.  (More to come.)

diff --git a/CHANGES.txt b/CHANGES.txt
index 76e401f..4f870c3 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -7,6 +7,9 @@
   * Added RemoveLast and SwapElements(index1, index2) to Reflection
     interface for repeated elements.
   * Added Swap(Message) to Reflection interface.
+  * Floating-point literals in generated code that are intended to be
+    single-precision now explicitly have 'f' suffix to avoid pedantic warnings
+    produced by some compilers.
 
 2009-05-13 version 2.1.0: