#6497: pass more information from the calling tool to ppx preprocessors
(tool name, some command-line arguments).

Corresponds to https://github.com/ocaml/ocaml/pull/85

Patch by Peter Zotov, with some modifications (mostly, the tool_name
is now passed explicitly instead of through a global reference).

Also rename Clflags.open_module to Clflags.open_modules and set
Clflags.for_package even in bytecode.





git-svn-id: http://caml.inria.fr/svn/ocaml/version/4.02@15062 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02