mingw dll support for grx247p1?

[Dimitar Zhekov]

Hi.

Now that grx246 (stable) is out, how about including the
MinGW dll support in 2.4.7pre1? You can find it as "mingw
DLL support", attachment <mingw-dll-supp.zip>, it applies
to grx246 with 1 line offset in makedefs.grx - or I can
re-diff/send it together with a slightly updated comment.

-- 
E-gards: Jimmy