+AC_ARG_ENABLE(gtk3,
+ AS_HELP_STRING([--enable-gtk3],
+ [Determines whether to use Gtk+ 3.0 vclplug on platforms where Gtk+ 3.0 is available.]),
+ [ac_cv_enable_gtk3=$enableval],[ac_cv_enable_gtk3=no])
+if test x"$ac_cv_enable_gtk3" = x"yes"; then
+ PKG_CHECK_MODULES(GTK, gtk+-3.0 >= 3.0 cairo)
+ AC_SUBST(GTK3, 1)
+else
+ PKG_CHECK_MODULES(GTK, gtk+-2.0 >= 2.10)
+ AC_SUBST(GTK2, 1)