It turned out that this is the solution: https://github.com/mbooth101/openldap
That allows you to build it using native Windows tools (like Visual Studio command prompt) so there is no risk of running into linking or other problems later on.
Can you explain to us what you mean by 'solution'?
I had a quick look at that URL and see no reference whatsoever about overlays, backends (e.g. ODBC, DB, SASL), dependencies (e.g. OpenSSL) and tests (approx. 70 tests)?
Cheers.