[Omake] filter-exists vs filter-targets in mk/make_gen

[Jason Hickey]

Aleksey Nogin wrote:
> I noticed that you've replaced the filter-targets calls in mk/make_gen 
> with filter-exists. This is bad as it will make the Makefiles incorrect 
> if you happen to build them before you build all the generated .ml/.mli 
> file. Is this change necessary?

Yes, because filter-targets may only be called once the build graph has 
been computed (the standard thing: "this may only be called in a rule 
body").

The "right" solution in this case is to delay evaluation until the 
Makefile rule is executed.  I had done that, but eventually undid it.

Jason

-- 
Jason Hickey                  http://www.cs.caltech.edu/~jyh
Caltech Computer Science      Tel: 626-395-6568 FAX: 626-792-4257