MinGW build instructions (was: PATCH: Use getche on Win32)

["Eli Zaretskii" <eliz@gnu.org>]

As an aside, what little experience I have in porting Unix programs to
MinGW tells me that setting up an environment to build a package is
not a trivial job.  There are issues with what shell to use and how to
set it up, what ports of auxiliary tools (Coreutils, Grep, Awk, etc.)
to use and how to set them up, what non-default libraries to install
and link against (the MinGW libraries such as libiberty, Libgw32c), etc.

So perhaps, if we are going to have an alive MinGW port, it is a good
idea to have a README.MinGW file in the distro that would describe how
to build such a port of GDB.  A description of the setup Mark uses to
work on the port would be a good starting point.

You can use the file gdb/config/djgpp/README as an example of solving
a similar problem, although the nature of the details is different, of
course.

TIA