diff -ru4NwbB libpng-1.4.6/png.h libpng-1.4.7rc01/png.h
--- libpng-1.4.6/png.h	2011-04-08 11:58:23.937816625 -0500
+++ libpng-1.4.7rc01/png.h	2011-04-08 20:51:19.917199114 -0500
@@ -155,8 +155,9 @@
  *    1.4.5                   14    10405  14.so.14.5[.0]
  *    1.4.6beta01-07          14    10406  14.so.14.6[.0]
  *    1.4.6rc01               14    10406  14.so.14.6[.0]
  *    1.4.6                   14    10406  14.so.14.6[.0]
+ *    1.4.7rc01               14    10407  14.so.14.7[.0]
  *
  *    Henceforth the source version will match the shared-library major
  *    and minor numbers; the shared-library major version number will be
  *    used for changes in backward compatibility, as it is intended.  The
diff -ru4NwbB libpng-1.4.6/pngwutil.c libpng-1.4.7rc01/pngwutil.c
--- libpng-1.4.6/pngwutil.c	2011-04-08 11:58:24.109706123 -0500
+++ libpng-1.4.7rc01/pngwutil.c	2011-04-08 20:51:20.087078761 -0500
@@ -681,8 +681,11 @@
           */
          if (length >= 2 &&
              png_ptr->height < 16384 && png_ptr->width < 16384)
          {
+            unsigned int z_cinfo;
+            unsigned int half_z_window_size;
+
             /* Compute the maximum possible length of the datastream */
 
             /* Number of pixels, plus for each row a filter byte and possible
              * and possibly a padding byte, so increase the maximum
@@ -699,10 +702,10 @@
             if (png_ptr->interlaced)
                uncompressed_idat_size += ((png_ptr->height + 7)/8) *
                    (png_ptr->bit_depth < 8 ? 12 : 6);
 
-            unsigned int z_cinfo = z_cmf >> 4;
-            unsigned int half_z_window_size = 1 << (z_cinfo + 7);
+            z_cinfo = z_cmf >> 4;
+            half_z_window_size = 1 << (z_cinfo + 7);
             while (uncompressed_idat_size <= half_z_window_size &&
                    half_z_window_size >= 256)
             {
                z_cinfo--;