diff --git a/ANNOUNCE b/ANNOUNCE
index 9be49af9f..4069e20f0 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,5 +1,5 @@
 
-Libpng 1.5.1rc02 - January 30, 2011
+Libpng 1.5.1rc02 - January 31, 2011
 
 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.
@@ -115,13 +115,13 @@ Version 1.5.1beta11 [January 28, 2011]
     architectures.
   Added transform tests to pngvalid and simplified the arguments.
 
-Version 1.5.1rc01 [January 30, 2011]
+Version 1.5.1rc01 [January 31, 2011]
   No changes.
 
-Version 1.5.1rc02 [January 30, 2011]
+Version 1.5.1rc02 [January 31, 2011]
   Added a request in the manual that applications do not use "png_" or
     "PNG_" to begin any of their own symbols.
-  Changed PNG_UNUSED to "(void)param;"
+  Changed PNG_UNUSED to "(void)param;" and updated the commentary in pngpriv.h
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net:
 (subscription required; visit
diff --git a/CHANGES b/CHANGES
index 10e99ac8f..121e517f4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3231,13 +3231,13 @@ Version 1.5.1beta11 [January 28, 2011]
     architectures.
   Added transform tests to pngvalid and simplified the arguments.
 
-Version 1.5.1rc01 [January 30, 2011]
+Version 1.5.1rc01 [January 31, 2011]
   No changes.
 
-Version 1.5.1rc02 [January 30, 2011]
+Version 1.5.1rc02 [January 31, 2011]
   Added a request in the manual that applications do not use "png_" or
     "PNG_" to begin any of their own symbols.
-  Changed PNG_UNUSED to "(void)param;"
+  Changed PNG_UNUSED to "(void)param;" and updated the commentary in pngpriv.h
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/pngpriv.h b/pngpriv.h
index d3903a960..30ac00473 100644
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -83,33 +83,14 @@ typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
 #  define PNG_MAX_MALLOC_64K
 #endif
 
-/* Unused formal parameter errors are removed using the following macro
- * which is expected to have no bad effects on performance.  Note that
- * if you replace it with something other than whitespace, you must include
- * the terminating semicolon.  Also note that some of these might not
- * work when "param" is a structure, but that is never the case in libpng.
+/* Unused formal parameter warnings are silenced using the following macro
+ * which is expected to have no bad effects on performance (optimizing
+ * compilers will probably remove it entirely).  Note that if you replace
+ * it with something other than whitespace, you must include the terminating
+ * semicolon.
  */
 #define PNG_UNUSED(param) (void)param;
 
-#if 0 /* Possibilities discussed on png-mng-implement, starting 27 Jan 2011 */
-#ifndef PNG_UNUSED                                 /* "best" but complex */
- #if defined(__GNUC__) || defined(_MSC_VER)
- #  define PNG_UNUSED(param) (void)param;
- #else
- #  define PNG_UNUSED(param)
- #endif
-#define PNG_UNUSED(param) {if(param){}}
-#define PNG_UNUSED(param) param = param;            /* What we used before */
-#define PNG_UNUSED(param) {(void)param;}            /* Visual C complains */
-#define PNG_UNUSED(param) if(param);                /* gcc-4.2 complains */
-#define PNG_UNUSED(param) if(param){}               /* more brackets nicer */
-#define PNG_UNUSED(param) ((void)(param ? 0 : 0));  /* 0:0 might be seen */
-#define PNG_UNUSED(param) {if(&param){}}            /* gcc-4 complains */
-#define PNG_UNUSED(param) {if(&param-&param){}}     /* No comment. */
-#define PNG_UNUSED(param) /* generates smallest (no) code but emits warning */
-#endif /* 0 */
-#endif /* PNG_UNUSED */
-
 /* Just a little check that someone hasn't tried to define something
  * contradictory.
  */