There existed (in past) an option to deploy portable software on Microsoft Windows systems through the use of Interix. However deploying Interix is tricky, sometimes it is impossible. Third-party software usually doesn't support running under Interix too, which reduces its utility.
MinGW present easier way to deploy familiar Unix-like environment. It is supported much better than Interix by upstream developers, and thus software is easier to get running correctly. It is easier than Interix to setup too.
Microsoft Windows is perhaps the only widespread platform that isn't supported by pkgsrc well enough. Unfortunately, pkgsrc needs to be adapted to run on MinGW. Note that obache has ported pkgsrc to Cygwin.
The goal of this project is to port pkgsrc tools to MinGW to the extent of building at least infrastructural packages.