Log Message:
Update to 1.5.2:

Version 1.5.2beta01 [February 13, 2011]
  More -Wshadow fixes for older gcc compilers.  Older gcc versions apparently
    check formal parameters names in function declarations (as well as
    definitions) to see if they match a name in the global namespace.
  Revised PNG_EXPORTA macro to not use an empty parameter, to accommodate the
    old VisualC++ preprocessor.
  Turned on interlace handling in png_read_png().
  Fixed gcc pendantic warnings.
  Handle longjmp in Cygwin.
  Fixed png_get_current_row_number() in the interlaced case.
  Cleaned up ALPHA flags and transformations.
  Implemented expansion to 16 bits.

Version 1.5.2beta02 [February 19, 2011]
  Fixed mistake in the descriptions of user read_transform and write_transform
    function prototypes in the manual.  The row_info struct is png_row_infop.
  Reverted png_get_current_row_number() to previous (1.5.2beta01) behavior.
  Corrected png_get_current_row_number documentation
  Fixed the read/write row callback documentation.
    This documents the current behavior, where the callback is called after
    every row with information pertaining to the next row.

Version 1.5.2beta03 [March 3, 2011]
  Fixed scripts/makefile.vcwin32
  Updated contrib/pngsuite/README to add the word "modify".
  Define PNG_ALLOCATED to blank when _MSC_VER<1300.

Version 1.5.2rc01 [March 19, 2011]
  Define remaining attributes to blank when MSC_VER<1300.
  ifdef out mask arrays in pngread.c when interlacing is not supported.

Version 1.5.2rc02 [March 22, 2011]
  Added a hint to try CPP=/bin/cpp if "cpp -E" fails in \ 
scripts/pnglibconf.mak
    and in contrib/pngminim/*/makefile, eg., on SunOS 5.10, and removed \ 
"strip"
    from the makefiles.
  Fixed a bug (present since libpng-1.0.7) that makes png_handle_sPLT() fail
    to compile when PNG_NO_POINTER_INDEXING is defined (Chubanov Kirill)

Version 1.5.2rc03 [March 24, 2011]
  Don't include standard header files in png.h while building the symbol table,
    to avoid cpp failure on SunOS (introduced PNG_BUILDING_SYMBOL_TABLE macro).

Version 1.5.2 [March 31, 2011]