Log Message:
Update to 1.2.9nb1:
. pngconf.h included "config.h" if HAVE_CONFIG_H is defined -- really not
  a good idea, patch it out. broke at least libwmf, reported by veego@
. install some libpng12 files -- IIUC, libpng12* is the future and
  libpng* is becoming obsolete -- at least according to the wishes of
  the authors. Don't follow this completely yet, but still patch the
  pkg-config file to link against -lpng instead of -lpng12, which
  would require a recursive PKGREVISION bump. We should probably do this
  at some future time.
. switch pkgconfig file to look for headers in include/libpng12 -- the
  headers still exist in include/ for backwards compatibility.
. switch to using GNU_CONFIGURE and the included libtool handling instead
  of patching in our own into a Makefile. Gets rid of patches and pkgsrc
  Makefile code.