Add option --recursive-process-input <filename> for use with
--recursive-process to specify the name of a file to use instead of
reading from stdin.
If --debug-output-dir is set, dump the file passed to the recursive
invocation of the compiler as a JSON file suitable for use with
--recursive-process-input.
These changes are intended to support debugging the compiler and are
only available with DEBUG builds.
Cyrill Leutwiler