[Omake] implicit rules with different scopes

[Alain Frisch]

Matthieu Dubuget wrote:
> I can't figure out a simple way to have both: special scope for some
> files, but still using implicit rules?
> 
> For example, I would like to let OMake apply implicit rules with a
> special environment (for example special OCAMLFLAGS) when working with
> file1.ml and apply the same implicit rules with another environment when
> working with file2.ml.

I think you can do something like:

section
   OCAMLFLAGS=....
   file1.cmx file1$(EXT_OBJ):
   file1.cmo:
   file1.cmo:

section
   OCAMLFLAGS=....
   file2.cmx file2$(EXT_OBJ):
   file2.cmo:
   file2.cmo:

That is, simply writing a rule with an empty body and with the same 
targets than those of the instance of an implicit rule attaches the 
current environment to this instance. I could not find it mentioned in 
the manual, but it seems to work (you can also add extra dependencies).

-- Alain