Merged example.c with libpng-1.2.37beta01

(from the git master branch)
diff --git a/CHANGES b/CHANGES
index 0617664..49cccb1 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2119,9 +2119,10 @@
   Rebuilt configure scripts with autoconf-2.63 instead of 2.62
   Removed pngprefs.h and MMX from makefiles
 
-version 1.4.0beta58 [May 3, 2009]
+version 1.4.0beta58 [May 13, 2009]
   Changed pngw32.def to pngwin.def in makefile.mingw (typo was intruduced
     in beta57).
+  Clarified usage of sig_bit versus sig_bit_p in example.c (Vincent Torri)
 
 version 1.4.0betaN [future]
   Build shared libraries with -lz and sometimes -lm.