It is a pointer, not an exported function.

    longjmp function as well as returning a pointer to the setjmp
    jmp_buf buffer, and marked direct access to jmpbuf 'deprecated'.
    (John Bowler)

around the call to png_flush() after png_write_IEND().  See 1.4.0beta32,
1.4.0beta50 changes above and 1.2.30, 1.2.30rc01 and rc03 in 1.2.41
CHANGES in the libpng_master branch.  Someone needs this feature but
I don't remember who.

from projects/visualc71/README_zlib.txt

into scripts/README.txt and updated the copyright year in scripts/pngwin.rc
from 2006 to 2009.

distributions (they are needed by CMakeList.txt).

and libpng-pc.in

    directory, to libpng-config.in and libpng-pc.in, respectively, and
    modified Makefile.am and configure.ac accordingly.  Now "configure"
    needs nothing from the "scripts" directory.
  Also, avoid redefining PNG_CONST in pngconf.h

Also netware.txt

(ported from the "master" branch)

(evidently the same change made in libpng-1.0beta54 was lost).

and removed the deprecated png_check_sig() function.

    so that only PNG_EXPORT functions are exported.