For historical reasons, "Win32" has been used in Rust codebase to mean "Windows OS in general".
This is confusing, especially now, that Rust supports Win64 builds.
[breaking-change]
Not included are two required patches:
* LLVM: segmented stack support for DragonFly [1]
* jemalloc: simple configure patches
[1]: http://reviews.llvm.org/D4705