Use gcc package on Linux

[jakirkham]

Fixes #2

Adds the gcc package on Linux to allow OpenMP to be distributed. However, that may change in the future.

Also, re-rendered with conda-smithy 0.9.2.

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I wanted to let you know that I linted all conda-recipes in your PR (recipe) and found some lint.

Here's what I've got...

For recipe:

• The recipe must have a build/number section.

[jakirkham]

Well that's clearly not true. Here's the build number.

[jakirkham]

This isn't actually failing. I just canceled some old jobs. There are new jobs that are running currently. Once we get their results, we should know if this worked correctly or not.

[ocefpaf]

@jakirkham I cancelled AppVeyor here because the build was hanging for almost an hour. Not sure if that is correct or if it is a bug.

[jakirkham]

Ack! I think I hacked this manually to do the right re-rendering before, but I re-rendered and it lost my hack. Should add an issue for conda-smithy.

[jakirkham]

Yeah, this hangs (when running the final built program) for some mysterious reason on Windows with VS 2008. I can't understand why, but I have opted to just skip it. If someone with Windows knowledge wants to take a look, I would certainly appreciate it.

[jakirkham]

In any event, I have added my hack back here so it shouldn't try to build on that platform again.

[jakirkham]

After resolving the re-rendering snafu, this appears to be working and is ready to go. Merging...