[openssl-dev] Make under windows

[Andy Polyakov]

> If you configure for mingw, you need to do so from inside a MSYS/MingW
> shell.  If you want to build inside a cmd shell, you have to configure
> natively,

In addition a "matching perl" is likely to be required. I mean one can
start MSYS shell and have ActiveState Perl first on the $PATH and that
is not directly supported combination. It might work, but if it doesn't,
we don't want to figure out why exactly. So one also better ensures that
MSYS shell calls MSYS perl. But one should keep in mind that "matching"
applies to build environment rather than configuration target. For
example one can compile for mingw not only from MSYS shell, but even
from within Cygwin and Linux. Probably most correct definition of
"matching" is "one that matches make utility".