ChangeLog: Enable builds as a CMake subproject
diff --git a/ChangeLog b/ChangeLog
index a461008..7579b5b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -103,6 +103,8 @@
    * Make it easier to define MBEDTLS_PARAM_FAILED as assert (which config.h
      suggests). #2671
    * Make `make clean` clean all programs always. Fixes #1862.
+   * Enable building of Mbed TLS as a CMake subproject. Suggested and fixed by
+     Ashley Duncan in #2609.
 
 = mbed TLS 2.17.0 branch released 2019-03-19