[lmi] MinGW gcc-4.3, and .tar.lzma

[Greg Chicares]

Here's a MinGW gcc-4.3 roadmap:
  http://article.gmane.org/gmane.comp.gnu.mingw.devel/2788
I'll look into building lmi with the alpha gcc binaries. We might
not be able to use it for production yet (I don't think it solves
the dll exception-handling problem
  http://cygwin.com/ml/cygwin/2008-04/msg00157.html
), but it might resolve the few remaining gcc issues with our
unit tests. And supporting one more compiler, even partially,
fits with work Vadim's doing with msvc and I'm doing with comeau
and borland; the benefit is that we can find weaknesses cheaply,
and therefore lower our long-term maintenance costs.

The size of MinGW gcc-4.3 alpha led to a discussion of archivers
  http://thread.gmane.org/gmane.comp.gnu.mingw.devel/2790/focus=2837
that contains some interesting speed and size measurements, along
with this comment:
  On 2008-04-06 21:49Z, Charles Wilson wrote:
| BTW, I noticed that the GNU packages are transitioning to .tar.lzma for
| their distributions
which leads me to think of using '.tar.lzma' for our production
distributions.