Add for-pack to pack sources automatically

[rgrinberg]

Attempt to make packs easier to construct by adding the -for-pack flag
to pack sources.

However I end up getting strange things like this in my project though:

*** omake: finished reading OMakefiles (0.09 sec)
*** omake:
   These file are targeted separately, but appear as effects of a single rule.
   This is likely to lead to unpredictable behavior.
   targets:
      compiler/outcometree.cmi
         (File omake/OCaml.om: line 556, characters 1-12)
      compiler/outcometree.o (File omake/OCaml.om: line 911, characters 6-21)
      compiler/outcometree.cmx
         (File omake/OCaml.om: line 911, characters 6-21)
*** omake:
   These file are targeted separately, but appear as effects of a single rule.
   This is likely to lead to unpredictable behavior.
   targets:
      compiler/outcometree.cmo
         (File omake/OCaml.om: line 533, characters 0-11)
      compiler/outcometree.o (File omake/OCaml.om: line 911, characters 6-21)
      compiler/outcometree.cmx
         (File omake/OCaml.om: line 911, characters 6-21)
*** omake:
   These file are targeted separately, but appear as effects of a single rule.
   This is likely to lead to unpredictable behavior.
   targets:
      compiler/annot.cmi (File omake/OCaml.om: line 556, characters 1-12)
      compiler/annot.o (File omake/OCaml.om: line 911, characters 6-21)
      compiler/annot.cmx (File omake/OCaml.om: line 911, characters 6-21)
*** omake:
   These file are targeted separately, but appear as effects of a single rule.
   This is likely to lead to unpredictable behavior.
   targets:
      compiler/annot.cmo (File omake/OCaml.om: line 533, characters 0-11)
      compiler/annot.o (File omake/OCaml.om: line 911, characters 6-21)
      compiler/annot.cmx (File omake/OCaml.om: line 911, characters 6-21)

So I doubt this is the correct fix. It would be great if this was done properly however.

[rgrinberg]

OK I fixed the above and it works. The only reason those $(BYTEDEPS) are there just so that those warnings go away. There's no need to pass -for-pack for bytecode objects and that's reflected in that we only add -for-pack to OCAMLOPTFLAGS

[rgrinberg]

@gerdstolpmann Ping? Anything I can do to improve this?

[rgrinberg]

@gerdstolpmann ping

[gerdstolpmann]

Frankly, I don't like the idea. So far OCamlPackage only affects linking, not compilation. This would be a fairly heavy change. It also breaks the concept that we take the values of the variables at the end of the OMakefile for compilation.

You could move that to a second function, e.g. OCamlCompileForPackage (or better name when you have an idea). That way it would be purely optional.

[rgrinberg]

That's fair, but I still think that creating a pack today with omake requires far too much ceremony. Do you have any other ideas on how to simplify this perhaps?