pythonPackages.cntk: mark as broken with python 3.7

[markuskowa]

Motivation for this change

The CNTK python module seems to be broken since November 2018 (does not recognize swig).
Mark it as broken.

Needs back port to 19.03 (#56826)

CC @costrouc @abbradar

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nix-review --run "nix-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.

---

[dotlambda]

Since #54182, swig needs to be in nativeBuildInputs.

[markuskowa]

@dotlambda thanks for the tip. It does find swig now but fails at later stage with a different error.

[dotlambda]

It fails with

unable to execute 'mpic++': No such file or directory

because openmpi isn't in nativeBuildInputs. However, I'm not sure if that one should remain in buildInputs too.

[markuskowa]

OK, that solves the mpic++ error but then we get the next error:

ImportError: cannot import name 'GenericMeta' from 'typing'

openmpi should probably remain in buildInputs since it is also a run time dependency.

[dotlambda]

ImportError: cannot import name 'GenericMeta' from 'typing'

See hsolbrig/PyShEx#17. I guess that needs to be fixed upstream by ctnk.

[markuskowa]

I restricted the broken attribute to python 3.7

@GrahamcOfBorg build python27Packages.cntk
@GrahamcOfBorg build python36Packages.cntk

[dotlambda]

I restricted the broken attribute to python 3.7

Perfect!

[markuskowa]

Thanks for the fixes!