libraries on windows

[Iain Buclaw]

== Quote from Kagamin (spam at here.lot)'s article
> Iain Buclaw Wrote:
> > Anyway, yes I believe this would be the expected behaviour. GDC has a slightly
> > different strategy than DMD to ensure symbols that are supposed to be only linked
> > once are done so correctly.
> Haha, just by making sure they're always linked? :)
> What is this strategy? I mean, wouldn't linker do it for you? I doubt it can
link a symbol twice, it will complain about duplicate symbols.

GDC marks decls as one-only, which for linux, puts symbols in a .gnu.linkonce section.