Update the changelog.
diff --git a/Changelog b/Changelog
index 526756b..adf7084 100644
--- a/Changelog
+++ b/Changelog
@@ -1,3 +1,6 @@
+2018-09-09:
+  Fix bug where large hex literals would lose their minus sign.
+
 2014-03-08:
   Update version number for cmake.
   Support shared libraries with cmake.