Native compilation for .ml and .mli files.
val implementation : 
  backend:(module Backend_intf.S) ->
  start_from:Clflags.Compiler_pass.t ->
  source_file:string ->
  output_prefix:string ->
  unitInternal functions
*
val clambda : 
  Compile_common.info ->
  (module Backend_intf.S) ->
  Typedtree.implementation ->
  unitclambda info typed applies the regular compilation pipeline to the given typechecked implementation and outputs the resulting files.
val flambda : 
  Compile_common.info ->
  (module Backend_intf.S) ->
  Typedtree.implementation ->
  unitflambda info backend typed applies the Flambda compilation pipeline to the given typechecked implementation and outputs the resulting files.

