Update changelog for cmake changes
diff --git a/ChangeLog b/ChangeLog
index 15ddee0..caf1309 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,7 @@
 = Branch 1.2
 Changes
    * Introduced POLARSSL_HAVE_READDIR_R for systems without it
+   * Improvements to the CMake build system, contributed by Julian Ospald.
 
 Security
    * Forbid change of server certificate during renegotiation to prevent