doc: note autoconf macro modernization in CHANGES

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

diff --git a/CHANGES b/CHANGES
index d853db75d45ff902fa74bd1820aa64d415d320bf..40b8265cf1e099bfbb6e37bcaf24c4255f19956c 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -3,6 +3,7 @@ RRDtool - master ...
 ====================
 Bugfixes
 --------
+* Modernize obsolete autoconf macros so configure regenerates cleanly with current autotools @oetiker
 
 Features
 --------