The tcl/win/README states this:
In order to compile Tcl for Windows, you need the following:
In the chatroom, kbk mentions that msys1.0 has been used for
some time now.
There is no need to specify a version. Just suggest fetching the latest version of msys and mingw.
Removed outdated Msys + Mingw info from win/README.
Removed outdated Msys + Mingw info from win/README in HEAD, core-8-5-branch and core-8-4-branch.