Add ChangeLog entry for redundant mutex initialization optimizations
diff --git a/ChangeLog b/ChangeLog
index 932e280..58139d0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -24,6 +24,9 @@
 
 Changes
    * Clarify the documentation of mbedtls_ssl_setup.
+   * Do not define global mutexes around readdir() and gmtime() in
+     configurations where the feature is disabled. Found and fixed by Gergely
+     Budai.
 
 = mbed TLS 2.7.1 branch released 2018-02-23