Changes made to pristine png source by mozilla.org developers. 2011/07/20 -- Synced with libpng-1.4.8 (bug #669863). 2011/04/08 -- Synced with libpng-1.4.7 (bug #624133). 2010/06/30 -- Synced with libpng-1.4.3 (bug #564792). 2010/02/26 -- Synced with libpng-1.4.1 (bug #544747). 2010/01/04 -- Synced with libpng-1.4.0 (bug #532645). 2009/09/10 -- Synced with libpng-1.2.40 (bug #492200 and #504805). Moved location of acTL chunk to just after IHDR in output PNG file. 2009/06/01 -- Eliminated incorrect test and rejection of APNG blend_op in opaque images (bug #441971 and #455140). 2009/05/17 -- Always clear prev_row for each APNG frame (bug #463465). 2009/02/19 -- Synced with libpng-1.2.35 (bug #478901). 2008/08/21 -- Synced with libpng-1.2.31 (bug #418900). 2008/03/29 -- Initialize prev_row for each APNG frame, only when the frame size increases (bug #420416). 2008/01/18 -- Synced with libpng-1.2.24 (bug #408429). 2007/11/13 -- Synced with libpng-1.2.23; Removed pnggccrd.c and pngvcrd.c; Reduced footprint by removing error and warning text (bug #403239) 2007/11/06 -- Synced with libpng-1.2.22 (removes MMX support) (bug #386585) 2007/07/27 -- Enabled cHRM and iCCP chunks for color management (bug #16769) 2007/05/05 -- Zeroed png_ptr->num_trans on CRC error (bug #374810) 2007/04/19 -- Synced with libpng-1.2.16 tree (bug #373249) 2007/03/20 -- Added support for APNG (bug #257197) 2006/06/27 -- Synced with libpng-1.2.12 tree (bug #334110) 2004/10/07 -- Synced with libpng-1.2.7 tree (bug #261922) 2004/10/07 -- Added mozpngconf.h (bug #208607)