Support for interop'ing with .NET via FFI declarations along the
lines of what Hugs98.NET offers, see

 http://haskell.org/pipermail/cvs-hugs/2003-March/001723.html

for FFI decl details.

To enable, configure with --enable-dotnet + have a look
in ghc/rts/dotnet/Makefile for details of what tools are needed to
build the .NET interop layer (tools from VS.NET / Framework SDK.)

The commit doesn't include some library additions + wider-scale
testing is required before this extension can be regarded as available
for general use. 'foreign import dotnet' is currently only supported
by the C backend.