-AM_PATH_GTK_2_0([2.16.0], [have_gtk=yes], [have_gtk=no])
-AM_CONDITIONAL([BUILD_LBXGUI], [test x"$have_gtk" = x"yes"])
+AM_CONDITIONAL([HAVE_LIBPNG], [$have_libpng])
+AS_IF([$have_libpng], [AC_DEFINE([HAVE_LIBPNG], [1],
+ [Define to 1 if libpng support is available])])
+
+AC_ARG_ENABLE([lbxgui],
+ [AS_HELP_STRING([--enable-lbxgui],
+ [build the lbxgui tool (requires GTK+) [default=auto]])],
+ [enable_lbxgui=$enableval],
+ [enable_lbxgui=auto])
+
+AS_CASE([$enable_lbxgui],
+ [no], [have_gtk=false],
+ [yes], [DX_CHECK_GTK2([2.16], [have_gtk=true])],
+ [DX_CHECK_GTK2([2.16], [have_gtk=true], [have_gtk=false])])
+
+AM_CONDITIONAL([BUILD_LBXGUI], [$have_gtk])