Add ChangeLog entry for clang version fix. Issue #1072
diff --git a/ChangeLog b/ChangeLog
index acecd71..1f20f44 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -18,6 +18,8 @@
 
 Changes
    * Support TLS testing in out-of-source builds using cmake.
+   * Changed the Clang parameters used in the CMake build files to work for
+     versions later than 3.6. Fixes #1072
 
 = mbed TLS 2.1.12 branch released 2018-04-30