__NHC__ ifdefs in the core libraries

[Ian Lynagh]

Hi all,

There are a couple of hundred ifdefs for __NHC__ in the core libraries,
but as far as I know nhc/yhc never switched over to the git repositories
for these libraries, and in any case I believe they are now considered
unmaintained projects.

Even if someone decides to resurrect them, it looks like most of the
ifdefs represent bugs that ought to be fixed (for example, Word being a
type synonym, [] needing to be im/exported, and an instance export bug).

Meanwhile, they make life harder for people working on the libraries:
When making a change, one feels that one ought to also update the NHC
alternative where appropriate, even though it has probably bitrotted
already, and despite not being able to test it.


So I propose that we remove all the __NHC__ ifdefs (and also base/NHC/)
in the core libraries. What do you think?


Thanks
Ian