diff --git a/m4/memopt.m4 b/m4/memopt.m4
new file mode 100644
index 0000000..4389752
--- /dev/null
+++ b/m4/memopt.m4
@@ -0,0 +1,15 @@
+AC_DEFUN([AC_MEM_OPT],
+[
+	AC_ARG_ENABLE(mem_opt,
+		AC_HELP_STRING([--enable-mem-opt],
+		               [enable best bit tree based memory optimizations]),
+		[use_mem_opt=$enableval],
+		[use_mem_opt=no])
+
+	if test "x$use_mem_opt" = "xyes"; then
+	MEM_OPT_FLAGS="-DMEM_OPT"
+	AC_SUBST(MEM_OPT_FLAGS)
+	fi
+])
+
+# vim: set ft=m4 ts=2 sw=2: