Remove i686-pc-mingw32

Fixes #400 and #492.

See #453.

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Remove i686-pc-mingw32 package recipes

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Merge pull request #529 from TimothyGu/mingw-dead

Remove i686-pc-mingw32