[Ecls-list] Mingw build fixes. Runtime still broken.

[Samium Gromoff]

Good day Juan and the list,

I have backported the mingw GC build fix and made one controversial
revert of the stream initialization, which breaks the build on mingw
-- but which, probably, is necessary on MSVC, which I didn't test.

These fixes make ECL build on mingw, but not make it run.
It fails, during init, with some kind of assertion exception,
which I wasn't able to trap using gdb.

The build fixes are on the mingw32-new branch on

    git://git.feelingofgreen.ru

This branch isn't tipped off today's master, but rather off yesterday.
Should be trivially cherrypickable, AFAICT.


regards, Samium Gromoff