Don't use the deprecated libtool m4-macros

Change-Id: Id2d3762fcdb6f7b2ad01d5cfe3d72994b9c75ca5
Reviewed-on: http://review.couchbase.org/24267
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>