Fix hardclock() with mingw64
diff --git a/ChangeLog b/ChangeLog
index 0b491b8..c545667 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,8 @@
 Features
 
 Bugfix
+   * Fix hardclock() (only used in the benchmarking program) with some
+     versions of mingw64 (found by kxjhlele).
 
 Changes
    * Move from SHA-1 to SHA-256 in example programs using signatures