Thanks to the PostgreSQL community, part of which I definitely am :), Tom Lane applied patches against 8.4 branch that fix problems with MinGW and BCC described in my previous posts:
- Building PostgreSQL client library using MinGW under WinXP SP3
- Building PostgreSQL client library using Borland C++ Compiler (BCC) under WinXP
So, my first patches (approved and edited by Tom I suppose) are applied! Kudos!