Hi Guix,

attached is a patch to add Julia, a language for technical computing,
and one more library it depends on: double-conversion.

The release tarball comes with all dependencies bundled, but I tried
hard to make it build against system libraries.  This didn't always
work, unfortunately.

libuv : Julia comes with a modified version of libuv and it won't build
        with our libuv package at this point.  This has been confirmed
        upstream[1].

dSMFT : Upstream's Makefile does not have targets to build dSMFT as a
        library.  The Makefile is only used to build test programmes.  I
        have a rudimentary package for dSMFT ready, but it would have to
        include a patch to the Makefile to actually build libraries.

rmath : Julia uses a version of rmath that is patched to use the dSMFT
        random number generator.  Upstream highly recommends using the
        patched library.

suitesparse : Unfortunately, suitesparse only builds static libraries,
        not shared ones, while Julia expects to find shared libraries.
        I'm not sure what to patch here: Julia's build system so that it
        builds shared libs from the suitesparse package output (rather
        than the bundled tarball) or suitesparse such that it also
        provides shared libs.

This package depends on a couple of other packages that are still
awaiting review:

- double-conversion (patch attached below)
- openblas[2] (needed because Julia doesn't build against Atlas)
- utf8proc[3]

TIA for the review!

~~ Ricardo

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[1]: https://github.com/JuliaLang/julia/issues/10246#issuecomment-75029026
[2]: http://lists.gnu.org/archive/html/guix-devel/2015-03/msg00557.html
[3]: http://lists.gnu.org/archive/html/guix-devel/2015-03/msg00563.html