This buffer is for notes you don't want to save, and for Lisp evaluation.
If you want to create a file, visit that file with C-x C-f,
then enter the text in that file's own buffer.
Interpreter FFI improvements:
* Support f-i dynamic.
* Correctly handle fns which don't return anything.
* Support x86 stdcall call-conv.
Clean-up of FFI-related code in ByteCodeGen.lhs.