ARROW-3925: [Python] Add autoconf to conda install instructions

[fjetter]

autoconf is required by the jemalloc build

[kszucs]

On long term we might want to prefer:

conda create -y -n pyarrow-dev -c conda-forge
--file arrow/ci/conda_env_cpp.yml
--file arrow/ci/conda_env_python.yml
python=3.6

which will be tested by the docker containers.

[kszucs]

jemalloc is not needed anymore

[fjetter]

There are cases for packages which I would like to install via conda, e.g. autoconf which are installed by the docker containers using apt-get. What should our approach be in these cases?

1. Add autoconf to the conda_env_cpp.yml and install it twice in the docker container?
2. Add autoconf to the conda_env_cpp.yml but don't install it using apt-get?
3. Don't put it in the file but on the cmd line, e.g. conda create -n pyarrow-dev autoconf --file ...?

@kszucs Do you have any preferences?

[kszucs]

@fjetter nice summary :) Go with the second.

[wesm]

@fjetter ping on this

[kszucs]

@wesm I'll finalize this PR.

What do You think about using

conda create -y -n pyarrow-dev -c conda-forge
--file arrow/ci/conda_env_cpp.yml
--file arrow/ci/conda_env_python.yml
python=3.6

in the development documentation?

[wesm]

That's fine with me. Fewer things to maintain

[wesm]

May have to use backslashes in the Windows version :)

[wesm]

Pinging about this

[kszucs]

@wesm pong

Dockerfile works cpp tests pass, pyarrow-dev install instruction works and pyarrow compiles (on OSX)

[wesm]

Hm, I think just single backslashes is OK? I will try it out on Windows before merging

[kszucs]

I'll render the docs, because I put those to escape the single backslash.

[kszucs]

Fixed it

[wesm]

+1. Thanks everyone!

[wesm]

Argh so one problem: autoconf is not cross-platform. Does this cause issues on Windows? I can test it out today if no one else has time

[kszucs]

@wesm I don't have a windows VM to test it

[wesm]

I will try it out on my Windows machine and merge if no issues

[wesm]

So we'll have to omit autoconf from conda_env_cpp.yml

(pyarrow-dev) λ conda create -n conda-env-test --file=ci\conda_env_cpp.yml python=3.6 Solving environment: failed PackagesNotFoundError: The following packages are not available from current channels: - autoconf Current channels: - https://conda.anaconda.org/conda-forge/win-64 - https://conda.anaconda.org/conda-forge/noarch - https://repo.anaconda.com/pkgs/main/win-64 - https://repo.anaconda.com/pkgs/main/noarch - https://repo.anaconda.com/pkgs/free/win-64 - https://repo.anaconda.com/pkgs/free/noarch - https://repo.anaconda.com/pkgs/r/win-64 - https://repo.anaconda.com/pkgs/r/noarch - https://repo.anaconda.com/pkgs/pro/win-64 - https://repo.anaconda.com/pkgs/pro/noarch - https://repo.anaconda.com/pkgs/msys2/win-64 - https://repo.anaconda.com/pkgs/msys2/noarch To search for alternate channels that may provide the conda package you're looking for, navigate to https://anaconda.org and use the search bar at the top of the page. 

[kszucs]

conda_env_unix.yml is missing, will resolve in #3059