Dump mingw-64's error codes into our source tree.
I have verified with these runes:
$ f=library/std/src/sys/windows/c/errors.rs
$ diff -ub <(git-cat-file blob HEAD~:$f | sort) <(cat $f | perl -pe 's/WSABASEERR \+ (\d+)/10000 + $1/e' |sort) |grep ^- |less
that this does not change any existing values.
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>