Remove conf-g++ dependency

[ncihnegn]

No description provided.

[dwang20151005]

Hey, thanks for sending this. The diff is in a file that is generated as part of our export process and the person who works on that is out for a couple of weeks. I'll get back to you when I can figure something out.

[dwang20151005]

Why do you want to remove this dependency?

Here's what I got by asking around internally:

We probably want to be sure a C++ compiler is available, which in some corner cases is not guaranteed. The only wait to test the change I can think of is to set up (typically using Docker) a Linux install such as the C compiler (used to build the opam switch) does not also support C++.

Since our best guess is that it fixes something in a scenario that we don't routinely test, I don't want to remove it unless it's actively causing problems somewhere else.

[ncihnegn]

In macOS it prevents installation because gcc is missing.

[ncihnegn]

Why not use conf-c++?

[dwang20151005]

@xclerc wdyt?

[xclerc]

Looking at the opam repository, it may
well be the case that we used conf-g++
because conf-c++ did not exist at the
time...

I think it is fine to change to conf-c++;
it is perhaps even better.

However, @ncihnegn, could you give
more details about the macOS failure.
I could not reproduce locally, and the
macOS boxes I have access to have
both /usr/bin/gcc and /usr/bin/g++.

[ncihnegn]

=== install 1 package
  ∗ conf-g++         1.0                      [required by re2]

The following system packages will first need to be installed:
    gcc

<><> Handling external dependencies <><><><><><><><><><><><><><><><><><><><>  🐫

opam believes some required external dependencies are missing. opam can:
> 1. Run brew to install them (may need root/sudo access)
  2. Display the recommended brew command and wait while you run it manually (e.g. in another
     terminal)
  3. Continue anyway, and, upon success, permanently register that this external dependency is
     present, but not detectable
  4. Abort the installation

[xclerc]

Thanks; I have never seen that on
macOS, and have brew in the
PATH.

I would suggest to change to
conf-c++.

[dwang20151005]

Thanks, Xavier, I will change to conf-c++.

[dwang20151005]

This change has been released internally. I've asked how long it'll take to make its way to github. I know the export is all automated now so I wouldn't expect that to take long.

[dwang20151005]

Ah, sorry, there is a manual step I didn't know about. It'll be about a month before you see the change on github.