wrong .def file name building with mingw

[Torbjorn Granlund]

I apologise for not having stopped this message from appearing on the
gmp bugs mailing, with its legal threats (in Italian).

I am removing it from the public archive.

To the author of the message: Please never send messages with legal
threats to the GNU mailing list.  If your employer appends these
threats, then please don't use their mail system to contact us.

-- 
Torbjörn