Fix old link in ChangeLog.

ChangeLog

@@ -10,7 +10,7 @@ Not all changes are documented here. In particular, new features, user-oriented
 Current trunk code
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  - To see a list of commits in the active development branch 'incoming', which have not yet been packaged in a release, see
-    https://github.com/kripken/emscripten/compare/1.7.8...incoming
+    https://github.com/kripken/emscripten/compare/1.8.2...incoming
 
 v1.8.2: 1/4/2013
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