The F# 2.0 distribution had a version of FSharp.Core compiled for WindowsPhone 7.1/Silverlight 4, but F# 3.0 doesn't, and the portable version only supports Silverlight 5 or Windows Phone 8. Has anyone been able to compile a version of FSharp.Core for F# 3.0 targeting Silverlight 4 or Windows Phone 7.1 from source? What are the defines required?
Edit:
On the fsharp compiler github repo, there's a target named portable-net4+sl4+wp71+win8, but in reality that's portable class library Profile47, which supposedly only support .NET 4.5, Silverlight 5.0 and Windows Store apps. It's the same as what's installed with VS2012. If you try to use it with a WP 7.1 project, it will fail at runtime complaining about missing IStructuralEquatable. It should really be named portable-net45+sl5+win8. There's a wp7 target also in the proj files, but it's currently not compiling
Got both the wp7 target and Portable88 target compiling from F# source after a couple of changes https://github.com/ovatsus/fsharp
Still need to thoroughly test at runtime, though