Revise Changelog to clarify and add credit
diff --git a/ChangeLog b/ChangeLog
index 9d591bb..641ce16 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -31,6 +31,8 @@
a contribution from Tobias Tangemann. #541
* Fixed cert_app sample program for debug output and for use when no root
certificates are provided.
+ * Fixed pthread implementation to avoid unintended double initialisations
+ and double frees. (found by Niklas Amnebratt)
* Fixed the sample applications gen_key.c, cert_req.c and cert_write.c for
builds where the configuration MBEDTLS_PEM_WRITE_C is not defined. Found
by inestlerode. #559.