Num library: introduce standalone package num.1.0

[xavierleroy]

The Num library (for arbitrary-precision integer and rational arithmetic) is no longer part of the core OCaml distribution since version 4.06.0 (more exactly: since commit ocaml/ocaml@967ff73).

This commit reflects this situation by

• stating that the "base-num" package is available for OCaml < 4.06.0
• adding a package num.1.0 for the standalone distribution of Num (https://github.com/ocaml/num)

[camelus]

❌ opam-lint errors 987d7a9

• base-num.base has errors:

  • error 21: Field 'opam-version' doesn't match the current version,
    validation may not be accurate: "1"
  • error 25: Missing field 'authors'
  • error 35: Missing field 'homepage'
  • warning 36: Missing field 'bug-reports'
  • warning 37: Missing field 'dev-repo'

• These packages passed lint tests: num.0, num.1.0

---

✅ Installability check (7288 → 7289)

• new installable packages (1): num.1.0

[xavierleroy]

Hurrah for CI, it found a typo in num-1.0/opam. Trying again...

[xavierleroy]

The tests are failing with OCaml 4.06, but I have the impression that they are using a cached version of OCaml 4.06 that still provides and installs the otherlibs/num library. On my local machine, opam switch 4.06.0+trunk followed by opam install num=1.0 work fine.

[avsm]

@xavierleroy the 4.06.0dev containers were indeed lagging by a few days. They're rebuilt now, so I'm restarting the CI.

[xavierleroy]

The problem is still there: in the log that starts with

=== Building opam install num.1.0 (b0867d)
[2017-08-22 11:35.26] Starting...

findlib/ocamlfind reports

- num: found

and proceeds to install the META file corresponding to the preinstalled Num library.

[avsm]

Sorry about this -- the opam2 container rebuild failed as the master branch has just shifted build systems, and this is blocking the ocaml-4.06.0dev rebuilds. They are unfortunately in lockstep for now. I'll manually test this and merge shortly, and CI can catch up.

[xavierleroy]

This is the packaging situation from hell ! Sorry about that, I didn't expect it to be that bad. It sure gives me pause as to splitting other libraries off the core OCaml distribution... At any rate, thanks @avsm for all the time you're devoting to this effort.

[avsm]

Manually tested and works on 4.06.0! These base transition packages are particularly thorny due to how intertwined they are with the compiler versions, so I appreciate you bearing with us while we get the right model for them in the opam repository. It feels good to absorb them into the package repo and unburden the compiler distribution -- please keep them coming!

opam2 should have a number of improvements to make their management easier. In the meanwhile, the various lint errors can be improved for these base packages.