diff --git a/ANNOUNCE b/ANNOUNCE
index ce54f401e..492c97252 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -132,7 +132,7 @@ version 1.5.0beta15 [March 17, 2010]
   Eliminated PNG_NO_EXTERN and PNG_ALL_EXTERN
 
 version 1.5.0beta16 [April 1, 2010]
-  Make png_text_struct independent of PNG_iTXt_SUPPORTED, so that
+  Made png_text_struct independent of PNG_iTXt_SUPPORTED, so that
     fields are initialized in all configurations.  The READ/WRITE
     macros (PNG_(READ|WRITE)_iTXt_SUPPORTED) still function as
     before to disable code to actually read or write iTXt chunks
@@ -140,6 +140,7 @@ version 1.5.0beta16 [April 1, 2010]
     read or write support (but it is probably better to check for
     the one actually required - read or write.)
   Combined multiple png_warning() calls for a single error.
+  Restored the macro definition of png_check_sig().
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/CHANGES b/CHANGES
index fb04654f8..80690e11e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2617,6 +2617,7 @@ version 1.5.0beta16 [April 1, 2010]
     read or write support (but it is probably better to check for
     the one actually required - read or write.)
   Combined multiple png_warning() calls for a single error.
+  Restored the macro definition of png_check_sig().
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/png.h b/png.h
index c704186be..7f0d18130 100644
--- a/png.h
+++ b/png.h
@@ -1,7 +1,7 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.5.0beta16 - March 30, 2010
+ * libpng version 1.5.0beta16 - April 1, 2010
  * Copyright (c) 1998-2010 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -11,7 +11,7 @@
  * Authors and maintainers:
  *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
  *   libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *   libpng versions 0.97, January 1998, through 1.5.0beta16 - March 30, 2010: Glenn
+ *   libpng versions 0.97, January 1998, through 1.5.0beta16 - April 1, 2010: Glenn
  *   See also "Contributing Authors", below.
  *
  * Note about libpng version numbers:
@@ -170,7 +170,7 @@
  *
  * This code is released under the libpng license.
  *
- * libpng versions 1.2.6, August 15, 2004, through 1.5.0beta16, March 30, 2010, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.5.0beta16, April 1, 2010, are
  * Copyright (c) 2004, 2006-2010 Glenn Randers-Pehrson, and are
  * distributed according to the same disclaimer and license as libpng-1.2.5
  * with the following individual added to the list of Contributing Authors:
@@ -282,7 +282,7 @@
  * Y2K compliance in libpng:
  * =========================
  *
- *    March 30, 2010
+ *    April 1, 2010
  *
  *    Since the PNG Development group is an ad-hoc body, we can't make
  *    an official declaration.
@@ -346,7 +346,7 @@
 /* Version information for png.h - this should match the version in png.c */
 #define PNG_LIBPNG_VER_STRING "1.5.0beta16"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.5.0beta16 - March 30, 2010\n"
+     " libpng version 1.5.0beta16 - April 1, 2010\n"
 
 #define PNG_LIBPNG_VER_SONUM   15
 #define PNG_LIBPNG_VER_DLLNUM  15
@@ -807,6 +807,11 @@ extern PNG_EXPORT(void,png_set_sig_bytes,(png_structp png_ptr,
 extern PNG_EXPORT(int,png_sig_cmp,(png_bytep sig, png_size_t start,
     png_size_t num_to_check),,3);
 
+/* Simple signature checking function.  This is the same as calling
+ * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
+ */
+#define png_check_sig(sig,n) !png_sig_cmp((sig), 0, (n))
+
 /* Allocate and initialize png_ptr struct for reading, and any other memory. */
 extern PNG_EXPORT(png_structp,png_create_read_struct,
     (png_const_charp user_png_ver, png_voidp error_ptr,