config,sb: Qemu build updates for FreeBSD and the start of MinG32.

Hack round the FreeBSD iconv support in Freebsd 10. In 10 libc now
supports iconv however iconv.h is present under /usr/local.

Start to add support to build qemu for MinGW via a Cxc. This is a
work in progress and contains lots of hidden traps.

In config.py separate out of the canadian build status.