-### Use -lpng if available, unless `--with-png=no'.
-### mingw32 doesn't use -lpng, since it loads the library dynamically.
-HAVE_PNG=no
-LIBPNG=
-if test "${opsys}" = "mingw32"; then
- if test "${with_png}" != "no"; then
- AC_CHECK_HEADER(png.h, HAVE_PNG=yes, HAVE_PNG=no)
- fi
- if test "${HAVE_PNG}" = "yes"; then
- AC_DEFINE(HAVE_PNG, 1, [Define to 1 if you have the png library (-lpng).])
-
- AC_CHECK_DECL(png_longjmp,
- [],
- [AC_DEFINE(PNG_DEPSTRUCT, [],
- [Define to empty to suppress deprecation warnings when building
- with --enable-gcc-warnings and with libpng versions before 1.5,
- which lack png_longjmp.])],
- [[#ifdef HAVE_LIBPNG_PNG_H
- # include <libpng/png.h>
- #else
- # include <png.h>
- #endif
- ]])
- fi
-elif test "${HAVE_X11}" = "yes" || test "${HAVE_W32}" = "yes"; then
- if test "${with_png}" != "no"; then
- # Debian unstable as of July 2003 has multiple libpngs, and puts png.h
- # in /usr/include/libpng.
- AC_CHECK_HEADERS(png.h libpng/png.h, break)
- if test "$ac_cv_header_png_h" = yes || test "$ac_cv_header_libpng_png_h" = yes ; then
- AC_CHECK_LIB(png, png_get_channels, HAVE_PNG=yes, , -lz -lm)
- fi
- fi
-
- if test "${HAVE_PNG}" = "yes"; then
- AC_DEFINE(HAVE_PNG, 1, [Define to 1 if you have the png library.])
-
- dnl Some systems, eg NetBSD 6, only provide eg "libpng16", not "libpng".
- lpng=`libpng-config --libs 2> /dev/null`
- case $lpng in
- -l*) : ;;
- *) lpng="-lpng" ;;
- esac
- LIBPNG="$lpng -lz -lm"
-
- AC_CHECK_DECL(png_longjmp,
- [],
- [AC_DEFINE(PNG_DEPSTRUCT, [],
- [Define to empty to suppress deprecation warnings when building
- with --enable-gcc-warnings and with libpng versions before 1.5,
- which lack png_longjmp.])],
- [[#ifdef HAVE_LIBPNG_PNG_H
- # include <libpng/png.h>
- #else
- # include <png.h>
- #endif
- ]])
- fi
-fi
-AC_SUBST(LIBPNG)
-