diff --git a/pngpriv.h b/pngpriv.h
index afc36b875..70eac1f53 100644
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -86,26 +86,28 @@ typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
 /* 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.
+ * 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.
  */
-#ifndef PNG_UNUSED
-#  define PNG_UNUSED(param) {if(param){}}
-/* Other possiblities being discussed on png-mng-implement, Jan 2011 */
-/* #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){}    */
-/* #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. */
-/*
- * #if defined(__GNUC__) || defined(_MSC_VER)
- * #  define UNUSED(param) (void)param;
- * #else
- * #  define UNUSED(param)
- * #endif
-*/
-#endif
+#define PNG_UNUSED(param) {if(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) 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.