diff --git a/ANNOUNCE b/ANNOUNCE
index 76d31c090..e939f5096 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,5 +1,5 @@
 
-Libpng 1.5.11rc06 - June 7, 2012
+Libpng 1.5.11rc06 - June 9, 2012
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -60,7 +60,8 @@ Version 1.5.11rc04 [June 6, 2012]
 Version 1.5.11rc05 [June 7, 2012]
   Don't check palette indexes if num_palette is 0 (as it can be in MNG files).
 
-Version 1.5.11rc06 [June 7, 2012]
+Version 1.5.11rc06 [June 9, 2012]
+  Include zlib.h in contrib/gregbook and visupng examples.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net:
 (subscription required; visit
diff --git a/CHANGES b/CHANGES
index b4e65d23c..b7d0400ab 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3888,7 +3888,8 @@ Version 1.5.11rc04 [June 6, 2012]
 Version 1.5.11rc05 [June 7, 2012]
   Don't check palette indexes if num_palette is 0 (as it can be in MNG files).
 
-Version 1.5.11rc06 [June 7, 2012]
+Version 1.5.11rc06 [June 9, 2012]
+  Include zlib.h in contrib/gregbook and visupng examples.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/contrib/gregbook/readpng.c b/contrib/gregbook/readpng.c
index df42c301b..0b75fac6d 100644
--- a/contrib/gregbook/readpng.c
+++ b/contrib/gregbook/readpng.c
@@ -55,8 +55,9 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <zlib.h>
 
-#include "png.h"        /* libpng header; includes zlib.h */
+#include "png.h"        /* libpng header */
 #include "readpng.h"    /* typedefs, common macros, public prototypes */
 
 /* future versions of libpng will provide this macro: */
diff --git a/contrib/gregbook/writepng.c b/contrib/gregbook/writepng.c
index f07f4a8a0..0dda62ea8 100644
--- a/contrib/gregbook/writepng.c
+++ b/contrib/gregbook/writepng.c
@@ -55,8 +55,9 @@
 
 
 #include <stdlib.h>     /* for exit() prototype */
+#include <zlib.h>
 
-#include "png.h"        /* libpng header; includes zlib.h and setjmp.h */
+#include "png.h"        /* libpng header, includes setjmp.h */
 #include "writepng.h"   /* typedefs, common macros, public prototypes */
 
 
diff --git a/contrib/visupng/PngFile.c b/contrib/visupng/PngFile.c
index ef0984e4d..dcde18a3a 100644
--- a/contrib/visupng/PngFile.c
+++ b/contrib/visupng/PngFile.c
@@ -13,6 +13,7 @@
 #include <commdlg.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <zlib.h>
 
 #include "png.h"
 #include "pngfile.h"
diff --git a/contrib/visupng/VisualPng.c b/contrib/visupng/VisualPng.c
index 009f120e3..236525a59 100644
--- a/contrib/visupng/VisualPng.c
+++ b/contrib/visupng/VisualPng.c
@@ -27,6 +27,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <windows.h>
+#include <zlib.h>
 
 /* application includes */