-have_gtk=no
-if test x"$enable_lbxgui" = x"auto"; then
-DX_CHECK_GTK2([2.16], [have_gtk=yes], [have_gtk=no])
-fi
-if test x"$enable_lbxgui" = x"yes"; then
-DX_CHECK_GTK2([2.16], [have_gtk=yes])
-fi
-AM_CONDITIONAL([BUILD_LBXGUI], [test x"$have_gtk" = x"yes"])
+AS_CASE([$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], [$have_gtk])
+
+DX_PROG_MD5SUM
+AS_IF([test x"$dx_cv_md5sum_works" = x"yes"],
+ [AC_SUBST([HAVE_MD5SUM], [true])],
+ [AC_SUBST([HAVE_MD5SUM], [false])])
+AC_SUBST([MD5SUM])