[devel] Revise CHANGES and ANNOUNCE

with information that the NULL dereference bug first appeared in libpng-0.95.
diff --git a/ANNOUNCE b/ANNOUNCE
index 5b03ea1..0e3d316 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -512,6 +512,7 @@
 
 version 1.4.0beta70 [July 28, 2009]
   Avoid a possible NULL dereference in debug build, in png_set_text_2().
+    (bug introduced in libpng-0.95, discovered by Evan Rouault)
 
 version 1.4.0betaN [future]
   Build shared libraries with -lz and sometimes -lm.
diff --git a/CHANGES b/CHANGES
index 18a39bc..dc0e8a9 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2191,6 +2191,7 @@
 
 version 1.4.0beta70 [July 28, 2009]
   Avoid a possible NULL dereference in debug build, in png_set_text_2().
+    (bug introduced in libpng-0.95, discovered by Evan Rouault)
 
 version 1.4.0betaN [future]
   Build shared libraries with -lz and sometimes -lm.