*W Windows DLL support currently quite limited due to platform limitations (see #5987)
Tier 2 platforms
Tier 2 platforms work (to varying degrees), but we rely on community support for
developing, testing, and building distributions. We may release GHC
with some Tier 2 platforms not working.
Platform-specific bugs on Tier 2 platforms are marked "low priority" (unless there's
a strong reason not to do so), not because they are unimportant to the users of that
platform, but to express the fact that they aren't going to hold up the release.
We'd like to promote as many
Tier 2 platforms as possible to Tier 1, as soon as they meet the Tier 1 criteria.
*S4 shared libraries are supported on Solaris 11 version 11/11 and higher
In most cases, binaries for the Tier 2 platforms can be downloaded from the Distribution Packages page, e.g. you can get binaries for most of the Linux platforms from Debian. In some cases, for example the Solaris platforms, you'll need to go to the download page of a particular release to get a bindist.
Tier 3 platforms
Tier 3 platforms worked in the past, but probably do not work now.