I'm one of the selected GSoC 2017 students under the Haiku Project  and I intend to add Haiku support to the Swift compiler and its standard libraries.  Haiku is an open-source operating system that specifically targets personal computing and aims to be a platform that is easy to use and learn for both end-users and developers, whilst retaining BeOS ABI compatibility . My plan is to only support 64 bit Haiku (x86_64-unknown-haiku) for now, 32 bit support is also a possibility but I’m not sure if this will get in the way of Swift’s goals? (IIRC there was a 32 bit Linux port that hasn’t been merged upstream.)
I have already patched the build-script and some other CMakeFiles for initial support in my swift fork, but they are based on the ’swift-3.1-branch' sources . As I plan to cleanup these changes and merge them upstream, should I be targeting my porting efforts to Swift 4 rather than Swift 3.1.1? My final proposal  documents the project timeline for executing this porting task.