Support "port" package manager (for OS X)

[eschnett]

The MacPorts system for OS X uses "port" as package manager, similar to apt-get for Ubuntu. These changes add support for it to BinDeps.

Installing MacPorts is non-trivial, i.e. takes about half an hour following instructions on the MacPorts web site. Unlike HomeBrew, MacPorts also does not support installing packages into arbitrary directories. It behaves more like apt-get, except that MacPorts is not shipped with OS X by default.

I thus think that Julia should not be trying to automatically install MacPorts. Rather, BinDeps should detect whether it is available, and if so, use it. This is why support should be provided by BinDeps directly, rather than a separate package MacPorts.

[IainNZ]

Out of curiosity, what does port get us that Homebrew doesn't?

[eschnett]

The reason I implemented this is that there is a library (hwloc) that I'm using, and which I installed via MacPorts. If BinDeps supports MacPorts, then installing hwloc is a no-op.

I tried installing it via HomeBrew first, but I couldn't find a HomeBrew recipe for hwloc. I only looked at one place, which seems to be the central HomeBrew place, but I'm unfamiliar with HomeBrew and may have missed secondary locations.

That is my other argument for MacPorts: It is older, and hence supports many more packages than HomeBrew.

[eschnett]

The Travis CI failure seems to be generic and unrelated to my changes.

[jakebolewski]

Hwloc is in the homebrew science repository Homebrew/legacy-homebrew#27949. I would support "blessing" hombrew as the solution for OS X.

[eschnett]

I'm unfamiliar with how homebrew specifies package names. What would the respective provides command be for hwloc? The lines below don't work:

using Homebrew
provides(Homebrew.HB, Dict("hwloc" => libhwloc))

The error from BinDeps.debug is:

      - Homebrew Bottles hwlocError: No available formula for hwloc 
 (can't provide)

[staticfloat]

If the formula is not within mainline Homebrew, the typical way to do this is to request the formula be added to Homebrew.jl (Or more specifically, to the homebrew-juliadeps tap, either place works), so that it can be bottled and made available to everyone by default. I think it would be best to provide installation of binary dependencies via only one path, so as to reduce the potential error surface and keep things as simple as possible. I've added it (staticfloat/homebrew-juliadeps@6e2cbe5) and bottled it (staticfloat/homebrew-juliadeps@f7418dd), so your Homebrew attempt above should be more successful now.

[eschnett]

Even if you don't like the idea of using port -- the last of the three commits in this pull request only adds documentation to the auto-generated file "deps.jl". That may still be useful

[staticfloat]

Can you rebase the first two commits out of this PR? I'm happy to merge the last one. :)

[eschnett]

Done; see #117 .

[staticfloat]

Cool, closing this one in favor of that one.