[Nix-dev] Update Julia to today's git

[Michael Raskin]

>>>Yes those fetchurl are my mistake and weren't used in the build anyway.
>>>I've however made it to use_system_mpfr and removed the useless fetchs
>>>(including the pcre source one which doesn't seem used).
>>>To do so I had to bump the mpfr version to 3.1.2.
>>>Patch attached. I'll be sure to setup a github fork soon.
>>
>> In trunk it is better to have two versions of MPFR, I think. GCC depends
>> on MPFR, so having two versions of MPFR is acceptable, but altering the
>> default MPFR version just because of Julia is a bad idea.

>I realize now that not everyone may want to do the full rebuild (gcc,
>coreutils, ...) I got by updating mpfr. The good way of doing this would
>then be to :
>- add the new mpfr .nix as 3.1.2.nix and restore the original default.nix
>- in the julia expresion replace the references to mpfr by mpfr-3.1.2
>The other way would be to let julia build the newer mpfr on each rebuild.
>Please correct me if I'm wrong.

Yes, you are right, and the first option seems our usual way.