diff --git a/ANNOUNCE b/ANNOUNCE
index 8d513d3dd..f2dc7be44 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -553,6 +553,8 @@ version 1.4.0beta80 [September 17, 2009]
 version 1.4.0beta81 [September 20, 2009]
   Eliminated unused PNG_FLAG_FREE_* defines from pngpriv.h
   Expanded TAB characters in pngrtran.c
+  Removed PNG_CONST from all "PNG_CONST PNG_CHNK" declarations to avoid
+    compiler complaints about doubly declaring things "const".
 
 version 1.4.0betaN [future]
   Build shared libraries with -lz and sometimes -lm.
diff --git a/CHANGES b/CHANGES
index 5e2cd3945..7f8ddbcbd 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2239,6 +2239,8 @@ version 1.4.0beta80 [September 17, 2009]
 version 1.4.0beta81 [September 20, 2009]
   Eliminated unused PNG_FLAG_FREE_* defines from pngpriv.h
   Expanded TAB characters in pngrtran.c
+  Removed PNG_CONST from all "PNG_CONST PNG_CHNK" declarations to avoid
+    compiler complaints about doubly declaring things "const".
 
 version 1.4.0betaN [future]
   Build shared libraries with -lz and sometimes -lm.
diff --git a/pngpread.c b/pngpread.c
index 563b7f4d4..e5a668bd2 100644
--- a/pngpread.c
+++ b/pngpread.c
@@ -1,7 +1,7 @@
 
 /* pngpread.c - read a png file in push mode
  *
- * Last changed in libpng 1.4.0 [September 17, 2009]
+ * Last changed in libpng 1.4.0 [September 20, 2009]
  * Copyright (c) 1998-2009 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.)
@@ -149,60 +149,60 @@ png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
 void /* PRIVATE */
 png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 {
-      PNG_CONST PNG_IHDR;
-      PNG_CONST PNG_IDAT;
-      PNG_CONST PNG_IEND;
-      PNG_CONST PNG_PLTE;
+      PNG_IHDR;
+      PNG_IDAT;
+      PNG_IEND;
+      PNG_PLTE;
 #if defined(PNG_READ_bKGD_SUPPORTED)
-      PNG_CONST PNG_bKGD;
+      PNG_bKGD;
 #endif
 #if defined(PNG_READ_cHRM_SUPPORTED)
-      PNG_CONST PNG_cHRM;
+      PNG_cHRM;
 #endif
 #if defined(PNG_READ_gAMA_SUPPORTED)
-      PNG_CONST PNG_gAMA;
+      PNG_gAMA;
 #endif
 #if defined(PNG_READ_hIST_SUPPORTED)
-      PNG_CONST PNG_hIST;
+      PNG_hIST;
 #endif
 #if defined(PNG_READ_iCCP_SUPPORTED)
-      PNG_CONST PNG_iCCP;
+      PNG_iCCP;
 #endif
 #if defined(PNG_READ_iTXt_SUPPORTED)
-      PNG_CONST PNG_iTXt;
+      PNG_iTXt;
 #endif
 #if defined(PNG_READ_oFFs_SUPPORTED)
-      PNG_CONST PNG_oFFs;
+      PNG_oFFs;
 #endif
 #if defined(PNG_READ_pCAL_SUPPORTED)
-      PNG_CONST PNG_pCAL;
+      PNG_pCAL;
 #endif
 #if defined(PNG_READ_pHYs_SUPPORTED)
-      PNG_CONST PNG_pHYs;
+      PNG_pHYs;
 #endif
 #if defined(PNG_READ_sBIT_SUPPORTED)
-      PNG_CONST PNG_sBIT;
+      PNG_sBIT;
 #endif
 #if defined(PNG_READ_sCAL_SUPPORTED)
-      PNG_CONST PNG_sCAL;
+      PNG_sCAL;
 #endif
 #if defined(PNG_READ_sRGB_SUPPORTED)
-      PNG_CONST PNG_sRGB;
+      PNG_sRGB;
 #endif
 #if defined(PNG_READ_sPLT_SUPPORTED)
-      PNG_CONST PNG_sPLT;
+      PNG_sPLT;
 #endif
 #if defined(PNG_READ_tEXt_SUPPORTED)
-      PNG_CONST PNG_tEXt;
+      PNG_tEXt;
 #endif
 #if defined(PNG_READ_tIME_SUPPORTED)
-      PNG_CONST PNG_tIME;
+      PNG_tIME;
 #endif
 #if defined(PNG_READ_tRNS_SUPPORTED)
-      PNG_CONST PNG_tRNS;
+      PNG_tRNS;
 #endif
 #if defined(PNG_READ_zTXt_SUPPORTED)
-      PNG_CONST PNG_zTXt;
+      PNG_zTXt;
 #endif
    /* First we make sure we have enough data for the 4 byte chunk name
     * and the 4 byte chunk length before proceeding with decoding the
@@ -726,7 +726,7 @@ png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
 void /* PRIVATE */
 png_push_read_IDAT(png_structp png_ptr)
 {
-   PNG_CONST PNG_IDAT;
+   PNG_IDAT;
    if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
    {
       png_byte chunk_length[4];
diff --git a/pngpriv.h b/pngpriv.h
index 2924f3171..fdc2031bb 100644
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -199,38 +199,39 @@
     (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )
 
 /* PNG_OUT_OF_RANGE returns true if value is outside the range
-   ideal-delta..ideal+delta.  Each argument is evaluated twice.
-   "ideal" and "delta" should be constants, normally simple
-   integers, "value" a variable. Added to libpng-1.2.6 JB */
+ * ideal-delta..ideal+delta.  Each argument is evaluated twice.
+ * "ideal" and "delta" should be constants, normally simple
+ * integers, "value" a variable. Added to libpng-1.2.6 JB
+ */
 #define PNG_OUT_OF_RANGE(value, ideal, delta) \
         ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
 
 /* Constant strings for known chunk types.  If you need to add a chunk,
- * define the name here, and add an invocation of the macro in png.c and
- * wherever it's needed.
+ * define the name here, and add an invocation of the macro wherever it's
+ * needed.
  */
-#define PNG_IHDR const png_byte png_IHDR[5] = { 73,  72,  68,  82, '\0'}
-#define PNG_IDAT const png_byte png_IDAT[5] = { 73,  68,  65,  84, '\0'}
-#define PNG_IEND const png_byte png_IEND[5] = { 73,  69,  78,  68, '\0'}
-#define PNG_PLTE const png_byte png_PLTE[5] = { 80,  76,  84,  69, '\0'}
-#define PNG_bKGD const png_byte png_bKGD[5] = { 98,  75,  71,  68, '\0'}
-#define PNG_cHRM const png_byte png_cHRM[5] = { 99,  72,  82,  77, '\0'}
-#define PNG_gAMA const png_byte png_gAMA[5] = {103,  65,  77,  65, '\0'}
-#define PNG_hIST const png_byte png_hIST[5] = {104,  73,  83,  84, '\0'}
-#define PNG_iCCP const png_byte png_iCCP[5] = {105,  67,  67,  80, '\0'}
-#define PNG_iTXt const png_byte png_iTXt[5] = {105,  84,  88, 116, '\0'}
-#define PNG_oFFs const png_byte png_oFFs[5] = {111,  70,  70, 115, '\0'}
-#define PNG_pCAL const png_byte png_pCAL[5] = {112,  67,  65,  76, '\0'}
-#define PNG_sCAL const png_byte png_sCAL[5] = {115,  67,  65,  76, '\0'}
-#define PNG_pHYs const png_byte png_pHYs[5] = {112,  72,  89, 115, '\0'}
-#define PNG_sBIT const png_byte png_sBIT[5] = {115,  66,  73,  84, '\0'}
-#define PNG_sPLT const png_byte png_sPLT[5] = {115,  80,  76,  84, '\0'}
-#define PNG_sRGB const png_byte png_sRGB[5] = {115,  82,  71,  66, '\0'}
-#define PNG_sTER const png_byte png_sTER[5] = {115,  84,  69,  82, '\0'}
-#define PNG_tEXt const png_byte png_tEXt[5] = {116,  69,  88, 116, '\0'}
-#define PNG_tIME const png_byte png_tIME[5] = {116,  73,  77,  69, '\0'}
-#define PNG_tRNS const png_byte png_tRNS[5] = {116,  82,  78,  83, '\0'}
-#define PNG_zTXt const png_byte png_zTXt[5] = {122,  84,  88, 116, '\0'}
+#define PNG_IHDR PNG_CONST png_byte png_IHDR[5] = { 73,  72,  68,  82, '\0'}
+#define PNG_IDAT PNG_CONST png_byte png_IDAT[5] = { 73,  68,  65,  84, '\0'}
+#define PNG_IEND PNG_CONST png_byte png_IEND[5] = { 73,  69,  78,  68, '\0'}
+#define PNG_PLTE PNG_CONST png_byte png_PLTE[5] = { 80,  76,  84,  69, '\0'}
+#define PNG_bKGD PNG_CONST png_byte png_bKGD[5] = { 98,  75,  71,  68, '\0'}
+#define PNG_cHRM PNG_CONST png_byte png_cHRM[5] = { 99,  72,  82,  77, '\0'}
+#define PNG_gAMA PNG_CONST png_byte png_gAMA[5] = {103,  65,  77,  65, '\0'}
+#define PNG_hIST PNG_CONST png_byte png_hIST[5] = {104,  73,  83,  84, '\0'}
+#define PNG_iCCP PNG_CONST png_byte png_iCCP[5] = {105,  67,  67,  80, '\0'}
+#define PNG_iTXt PNG_CONST png_byte png_iTXt[5] = {105,  84,  88, 116, '\0'}
+#define PNG_oFFs PNG_CONST png_byte png_oFFs[5] = {111,  70,  70, 115, '\0'}
+#define PNG_pCAL PNG_CONST png_byte png_pCAL[5] = {112,  67,  65,  76, '\0'}
+#define PNG_sCAL PNG_CONST png_byte png_sCAL[5] = {115,  67,  65,  76, '\0'}
+#define PNG_pHYs PNG_CONST png_byte png_pHYs[5] = {112,  72,  89, 115, '\0'}
+#define PNG_sBIT PNG_CONST png_byte png_sBIT[5] = {115,  66,  73,  84, '\0'}
+#define PNG_sPLT PNG_CONST png_byte png_sPLT[5] = {115,  80,  76,  84, '\0'}
+#define PNG_sRGB PNG_CONST png_byte png_sRGB[5] = {115,  82,  71,  66, '\0'}
+#define PNG_sTER PNG_CONST png_byte png_sTER[5] = {115,  84,  69,  82, '\0'}
+#define PNG_tEXt PNG_CONST png_byte png_tEXt[5] = {116,  69,  88, 116, '\0'}
+#define PNG_tIME PNG_CONST png_byte png_tIME[5] = {116,  73,  77,  69, '\0'}
+#define PNG_tRNS PNG_CONST png_byte png_tRNS[5] = {116,  82,  78,  83, '\0'}
+#define PNG_zTXt PNG_CONST png_byte png_zTXt[5] = {122,  84,  88, 116, '\0'}
 
 
 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
diff --git a/pngread.c b/pngread.c
index 9c3ab05db..7caa14e06 100644
--- a/pngread.c
+++ b/pngread.c
@@ -1,7 +1,7 @@
 
 /* pngread.c - read a PNG file
  *
- * Last changed in libpng 1.4.0 [September 17, 2009]
+ * Last changed in libpng 1.4.0 [September 20, 2009]
  * Copyright (c) 1998-2009 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.)
@@ -231,60 +231,60 @@ png_read_info(png_structp png_ptr, png_infop info_ptr)
 
    for (;;)
    {
-      PNG_CONST PNG_IHDR;
-      PNG_CONST PNG_IDAT;
-      PNG_CONST PNG_IEND;
-      PNG_CONST PNG_PLTE;
+      PNG_IHDR;
+      PNG_IDAT;
+      PNG_IEND;
+      PNG_PLTE;
 #if defined(PNG_READ_bKGD_SUPPORTED)
-      PNG_CONST PNG_bKGD;
+      PNG_bKGD;
 #endif
 #if defined(PNG_READ_cHRM_SUPPORTED)
-      PNG_CONST PNG_cHRM;
+      PNG_cHRM;
 #endif
 #if defined(PNG_READ_gAMA_SUPPORTED)
-      PNG_CONST PNG_gAMA;
+      PNG_gAMA;
 #endif
 #if defined(PNG_READ_hIST_SUPPORTED)
-      PNG_CONST PNG_hIST;
+      PNG_hIST;
 #endif
 #if defined(PNG_READ_iCCP_SUPPORTED)
-      PNG_CONST PNG_iCCP;
+      PNG_iCCP;
 #endif
 #if defined(PNG_READ_iTXt_SUPPORTED)
-      PNG_CONST PNG_iTXt;
+      PNG_iTXt;
 #endif
 #if defined(PNG_READ_oFFs_SUPPORTED)
-      PNG_CONST PNG_oFFs;
+      PNG_oFFs;
 #endif
 #if defined(PNG_READ_pCAL_SUPPORTED)
-      PNG_CONST PNG_pCAL;
+      PNG_pCAL;
 #endif
 #if defined(PNG_READ_pHYs_SUPPORTED)
-      PNG_CONST PNG_pHYs;
+      PNG_pHYs;
 #endif
 #if defined(PNG_READ_sBIT_SUPPORTED)
-      PNG_CONST PNG_sBIT;
+      PNG_sBIT;
 #endif
 #if defined(PNG_READ_sCAL_SUPPORTED)
-      PNG_CONST PNG_sCAL;
+      PNG_sCAL;
 #endif
 #if defined(PNG_READ_sPLT_SUPPORTED)
-      PNG_CONST PNG_sPLT;
+      PNG_sPLT;
 #endif
 #if defined(PNG_READ_sRGB_SUPPORTED)
-      PNG_CONST PNG_sRGB;
+      PNG_sRGB;
 #endif
 #if defined(PNG_READ_tEXt_SUPPORTED)
-      PNG_CONST PNG_tEXt;
+      PNG_tEXt;
 #endif
 #if defined(PNG_READ_tIME_SUPPORTED)
-      PNG_CONST PNG_tIME;
+      PNG_tIME;
 #endif
 #if defined(PNG_READ_tRNS_SUPPORTED)
-      PNG_CONST PNG_tRNS;
+      PNG_tRNS;
 #endif
 #if defined(PNG_READ_zTXt_SUPPORTED)
-      PNG_CONST PNG_zTXt;
+      PNG_zTXt;
 #endif
       png_uint_32 length = png_read_chunk_header(png_ptr);
       PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
@@ -445,7 +445,7 @@ png_start_read_image(png_structp png_ptr)
 void PNGAPI
 png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
 {
-   PNG_CONST PNG_IDAT;
+   PNG_IDAT;
    PNG_CONST int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
       0xff};
    PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
@@ -802,60 +802,60 @@ png_read_end(png_structp png_ptr, png_infop info_ptr)
 
    do
    {
-      PNG_CONST PNG_IHDR;
-      PNG_CONST PNG_IDAT;
-      PNG_CONST PNG_IEND;
-      PNG_CONST PNG_PLTE;
+      PNG_IHDR;
+      PNG_IDAT;
+      PNG_IEND;
+      PNG_PLTE;
 #if defined(PNG_READ_bKGD_SUPPORTED)
-      PNG_CONST PNG_bKGD;
+      PNG_bKGD;
 #endif
 #if defined(PNG_READ_cHRM_SUPPORTED)
-      PNG_CONST PNG_cHRM;
+      PNG_cHRM;
 #endif
 #if defined(PNG_READ_gAMA_SUPPORTED)
-      PNG_CONST PNG_gAMA;
+      PNG_gAMA;
 #endif
 #if defined(PNG_READ_hIST_SUPPORTED)
-      PNG_CONST PNG_hIST;
+      PNG_hIST;
 #endif
 #if defined(PNG_READ_iCCP_SUPPORTED)
-      PNG_CONST PNG_iCCP;
+      PNG_iCCP;
 #endif
 #if defined(PNG_READ_iTXt_SUPPORTED)
-      PNG_CONST PNG_iTXt;
+      PNG_iTXt;
 #endif
 #if defined(PNG_READ_oFFs_SUPPORTED)
-      PNG_CONST PNG_oFFs;
+      PNG_oFFs;
 #endif
 #if defined(PNG_READ_pCAL_SUPPORTED)
-      PNG_CONST PNG_pCAL;
+      PNG_pCAL;
 #endif
 #if defined(PNG_READ_pHYs_SUPPORTED)
-      PNG_CONST PNG_pHYs;
+      PNG_pHYs;
 #endif
 #if defined(PNG_READ_sBIT_SUPPORTED)
-      PNG_CONST PNG_sBIT;
+      PNG_sBIT;
 #endif
 #if defined(PNG_READ_sCAL_SUPPORTED)
-      PNG_CONST PNG_sCAL;
+      PNG_sCAL;
 #endif
 #if defined(PNG_READ_sPLT_SUPPORTED)
-      PNG_CONST PNG_sPLT;
+      PNG_sPLT;
 #endif
 #if defined(PNG_READ_sRGB_SUPPORTED)
-      PNG_CONST PNG_sRGB;
+      PNG_sRGB;
 #endif
 #if defined(PNG_READ_tEXt_SUPPORTED)
-      PNG_CONST PNG_tEXt;
+      PNG_tEXt;
 #endif
 #if defined(PNG_READ_tIME_SUPPORTED)
-      PNG_CONST PNG_tIME;
+      PNG_tIME;
 #endif
 #if defined(PNG_READ_tRNS_SUPPORTED)
-      PNG_CONST PNG_tRNS;
+      PNG_tRNS;
 #endif
 #if defined(PNG_READ_zTXt_SUPPORTED)
-      PNG_CONST PNG_zTXt;
+      PNG_zTXt;
 #endif
       png_uint_32 length = png_read_chunk_header(png_ptr);
       PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;