Fix AVX/AVX2 issues with prebuilt ponyc

[SeanTAllen]

We regularly get issues opened from people having problems
with the prebuilt pony packages where their platform
doesn't support AVX or AVX2 and the prebuilt packages were
built with that on.

This commit should get us building with the simplest of baselines
for users and allow them to run without issue.

The arch= idea is Sylvan's.

[SeanTAllen]

I'm looking at the appveyor setup and I'm not sure what the corresponding change there is. @kulibali or @killerswan can you point me in the right direction?

What I want, pass -arch= when building if the branch is release.

[SeanTAllen]

@ponylang/committer the other options for this would be to never run ci with AVX etc and do all builds with arch=. Thoughts?

[SeanTAllen]

@sylvanc and I believe this should address #1661.

[SeanTAllen]

Also, if we agree this is the correct approach, we should figure out if we need to update the homebrew formula. As no one on a mac as reported an issue for this, I'd say we don't.

[dipinhora]

Would also address #1331.

[SeanTAllen]

Bonus!

[SeanTAllen]

@jemc the illegal instruction issue apparently impacts on the Docker image as well. I'm pretty ignorant on the docker front. What do we need to do to address with it?

[jemc]

@SeanTAllen - you should be able to add the same arch= fix to this line of the Dockerfile, where make is invoked:

ponyc/Dockerfile

Line 27 in ec6f9b1

RUN make \

It probably makes sense to do it in this same PR, I think.

[SeanTAllen]

@jemc pushed a change to include that

[chalcolith]

For AppVeyor, the Windows build currently does not compile with either AVX or AVX2.

[SeanTAllen]

@kulibali is that via -arch=?

[chalcolith]

There's no -arch flag for the WAF script on Windows. To compile with AVX or AVX2 you can use CXXFLAGS, e.g.:

make configure CXXFLAGS=/arch:AVX
make build test

To make permanent changes you can modify the assignments to msvcDebugFlags and msvcReleaseFlags in the wscript file.

[SeanTAllen]

@jemc so you are good with this approach and merging or do we wait til Wednesday?

[killerswan]

@you'll also want to modify the README (line ~385) section about AVX, and perhaps the section below it.

Are there any other flags in native (see here and here) which we'll want to re-add manually?

[jemc]

@SeanTAllen I'm fine with merging before Wednesday, if all your questions are resolved before then.

However, seems like @killerswan now has some outstanding concerns to resolve.

[SeanTAllen]

@killerswan i'd say this is a good place to start from and we could add things back in. in general, i think it's reasonable to say "if you want best performance, build from source".

[SeanTAllen]

@killerswan README updated. Nice catch. Thanks.

[SeanTAllen]

If this passes, I'm going to merge and do a release so we can take care of the issues that people are currently hitting and we can always revisit the...

Are there any other flags in native (see here and here) which we'll want to re-add manually?

issue that @killerswan raised.

[SeanTAllen]

I'm leaving on the "needs discussion during sync" so we can discuss the additional issues re: native and "should we change OSX" and "should we use -arch= for all CI builds not just release`

[SeanTAllen]

People are still reporting this as a problem. Apparently either

1. i implemented this wrong
2. sylvan's idea fix the problem

[killerswan]

In the diff I notice that one place you call make arch=, and in another make -arch=...

[SeanTAllen]

sadly its the docker on that is incorrect.

[SeanTAllen]

so i did it correctly for what i changed in travis