This adds the OS check for the Haiku operating system, as it was missing in the Triple class. Tests for x86_64-unknown-haiku and i586-pc-haiku were also added.
These patches only affect Haiku and are completely harmless for other platforms.
This patch is needed in-tree for upstreaming my Swift port for Haiku, which is part of my Google Summer of Code project.
The swift-llvm fork regularly pulls changes from LLVM master into the upstream-with-swift branch, so adding this patch here should make sense.
I also don't have commit access, so could you commit this patch?