-])], [libpng_cv_sufficient_ver=yes], [libpng_cv_sufficient_ver=no])])
-])
-
-dnl CHECK_LIBPNG([min-version], [action-if-ok], [action-if-fail])
-AC_DEFUN([CHECK_LIBPNG],
-[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
-AC_ARG_VAR([LIBPNG_CFLAGS], [C compiler flags for libpng])dnl
-AC_ARG_VAR([LIBPNG_LIBS], [linker flags for libpng])dnl
-
-if test x"$PKG_CONFIG" != x; then
- AC_MSG_CHECKING([pkg-config database for libpng])
- _PKG_CONFIG([libpng_cflags], [cflags], [libpng])
- _PKG_CONFIG([libpng_libs], [libs], [libpng])
- if test x$pkg_failed = xyes; then
- errors=`$PKG_CONFIG --errors-to-stdout --print-errors libpng`
- echo "$errors" >&AS_MESSAGE_LOG_FD
- AC_MSG_RESULT([no])
- else
- if test x"$LIBPNG_CFLAGS" = x; then
- LIBPNG_CFLAGS=$pkg_cv_libpng_cflags
- fi
- if test x"$LIBPNG_LIBS" = x; then
- LIBPNG_LIBS=$pkg_cv_libpng_libs
- fi
-
- AC_MSG_RESULT([yes])
- fi
-fi
-
-if test x"$LIBPNG_LIBS" = x; then
- LIBPNG_LIBS=-lpng
-fi
-
-AC_LANG_PUSH([C])
-old_cflags=$CFLAGS
-old_libs=$LIBS
-CFLAGS="$LIBPNG_CFLAGS $CFLAGS"
-LIBS="$LIBPNG_LIBS $LIBS"
-
-_LIBPNG_TRY_VERSION(ifelse([$1], [], [1.0], [$1]))
-
-CFLAGS=$old_cflags
-LIBS=$old_libs
-AC_LANG_POP([C])
-
-if test x"$libpng_cv_sufficient_ver" = x"yes"; then
- AC_SUBST([LIBPNG_CFLAGS])
- AC_SUBST([LIBPNG_LIBS])
- ifelse([$2], [], [true], [$2])
+])])
+
+dnl DX_CHECK_LIBPNG([min-version], [action-if-ok], [action-if-fail])
+AC_DEFUN([DX_CHECK_LIBPNG],
+[DX_PKG_CONFIG([libpng], [libpng], [libpng])
+
+DX_CHECK_LIB([libpng],
+ [for libpng[]ifelse([$1], [], [], [ version at least $1])],
+ [m4_apply([_DX_LIBPNG_TEST_PROGRAM], m4_split([$1], [\.]))], [dnl
+ [[$LIBPNG_CFLAGS], [$LIBPNG_LIBS]],
+ [[$pkg_cv_libpng_cflags], [$pkg_cv_libpng_libs],
+ [test ! x"$pkg_failed" = x"yes"]],
+ [[], [-lpng]],
+ ])
+
+if test x"$dx_cv_libpng_found" = x"yes"; then
+ ifelse([$2], [], [:], [$2])